GMAT Critical Reasoning - everything you need to know

GMAT Critical Reasoning - Everything you need to know

This slideshow features screenshots from GMAT Prep Now’s entire Critical Reasoning module (consisting of 38 videos). It covers everything you need to know, and it includes 24 practice questions.

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Note: since these slides are just snippets of a full-length video course, there may be times when you’re unable to glean all the relevant information from a particular screenshot. If, at any time, you’d like to watch the entire video on a certain topic, just click on the link at the top of that page, and you’ll be taken that that particular video.



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Introduction to Critical Reasoning (watch the entire video here)


http://www.gmatprepnow.com/module/gmat-critical-reasoning/video/1132

This lesson features GMAT questions from the GMAT® mini-test.

GMAT® questions are the property of the Graduate Management Admission Council® and are used here with their permission.




• About 1/3 of Verbal questions (13 to 15 questions)

• Batches of 2 or 3 questions

• Approximately 2 minutes per question

• Test your ability to reason effectively




Introduction to Critical Reasoning

The average normal infant born in the United States weighs between twelve and fourteen pounds at the age of three months. Therefore, if a three-month-old child weighs only ten pounds, its weight gain has been below the United States average.

Which of the following indicates a flaw in the reasoning above?

A) Weight is only one measure of normal infant development.

B) Some three-month-old children weigh as much as seventeen pounds.

C) It is possible for a normal child to weigh ten pounds at birth.

D) The phrase "below average" does not necessarily mean insufficient.

E) Average weight gain is not the same as average weight.

Passage

(watch the entire video here)











Passage

Question stem












Passage

Question stem

Answer choices









• Arguments consist of premises and a conclusion

• Conclusion: what the author is trying to convince you of

• Premises: the evidence used to support the conclusion





Premise: All men are mortal Premise: Socrates is a man

All men are mortal. Socrates is a man. Therefore, Socrates is mortal.

Conclusion: Socrates is mortal

+

Premise: Gary late for last 3 days Premise: Flat tire this morning

Conclusion: Gary will be late today

+

Strength of an Argument: How well the conclusion follows from the premises

Inductive: the conclusion is not guaranteed

Deductive: the conclusion is guaranteed

For the past 3 days, Gary has arrived late for work. This morning, while Gary was driving to work, his car got a flat tire.

Therefore, Gary will be late for work today.






Strengthen

Strengthen



For the past 53 days, Gary has arrived late for work. This morning, while Gary

was driving to work, his car got a flat tire. Therefore, Gary will be late for work today.

For the past 53 days, Gary has arrived late for work. This morning, while Gary was driving to work, his car got 4 flat

tires, and his engine exploded. Therefore, Gary will be late for work today.






Weaken



For the past 3 days, Gary has arrived late for work. This morning, while Gary was driving to work, his car got a flat tire. Gary’s house is 1 block from work.







• The conclusions in most arguments are not guaranteed

• Most arguments can be strengthened or weakened by adding/altering premises







Strength of an Argument

How well the conclusion follows from the premises

Accept all premises as true!







All pigs can fly. Mount Everest is a pig. Therefore, Mount Everest can fly.






All pigs can fly. Mount Everest is a pig. Therefore, Mount Everest cannot fly.













• Assumption(s): unstated premise(s) necessary to reach conclusion





Assumptions: • Gary’s history of lateness will be repeated today

• The time needed to change tire will exceed the time before work starts

• Gary has no other means by which to arrive at work on time







Premise(s)

Conclusion

+ Assumption(s)












• Assumption(s): unstated premise(s) necessary to reach conclusion

Strength of an Argument: How well the conclusion follows

from the premises





Dissecting an Argument (watch the entire video here)



Dissecting an Argument

Every hockey fan I know is nice. I do not know Judy, but since she is wearing a hockey jersey, she must be nice.

Summarize: - the conclusion

- the premises

- any assumptions





“Is this what the author is trying to convince me of?”


Conclusion: J is nice






Goal: make your summaries as brief as possible (while maintaining coherence)








Premise: All H-fans I know are nice Premise: I don’t know J Premise: J wearing jersey

+ Assumption: The H-fans I know are representative Assumption: Wearing jersey makes one a fan





Researcher: Two years ago, a wolf pack was relocated to Bilford Island. Although the local rabbit population has decreased drastically since the relocation, the wolves are not to blame for this decrease. Our study shows that the unprecedented number of recent rabbit deaths is due to the myxoma virus.


- the premises

- any assumptions





Premise-Therefore-Conclusion test


Option A: wolves not to blame therefore virus killed rabbits

Option B: virus killed rabbits therefore wolves not to blame





Conclusion: rabbit pop. not wolves’ fault

+


Premise: wolves arrived 2 yrs ago Premise: rabbit pop. since Premise: virus caused deaths

Assumption: wolves didn’t contribute to virus





Tips for Identifying Conclusions and Premises

• Watch for trigger words that indicate a conclusion

• Watch for trigger words that indicate a premise

therefore, thus, hence, so, implies, indicates, consequently, as a result, clearly, accordingly, infer, conclude

since, because, for, due to, evidence, on the basis of, given that

• Beware of common argument structures

1. Premise, premise, . . . , conclusion

2. Conclusion, premise, premise . . .

3. Conclusion in the question stem






- the premises

- any assumptions

Until recently, the only fish species living in Chilliwack Lake was the Gigafish. Last month, however, several Sovkafish were spotted in the lake. Unlike Gigafish, Sovkafish do not eat insects; instead, they survive by eating other fish. In other lakes where Sovkafish exist, their populations are limited by Dragonfish, which like to feed on Sovkafish.

Which of the following, if true, most effectively challenges the conclusion that releasing 100 Dragonfish into Chilliwack Lake will allow the Gigafish in Chilliwack Lake to survive?





Until recently, the only fish species living in Chilliwack Lake was the Gigafish. Last month, however, several Sovkafish were spotted in the lake. Unlike Gigafish, Sovkafish do not eat insects; instead, they survive by eating other fish. In other lakes where Sovkafish exist, their populations are limited by Dragonfish, which like to feed on Sovkafish.

Which of the following, if true, most effectively challenges the conclusion that releasing 100 Dragonfish into Chilliwack Lake will allow the Gigafish in Chilliwack Lake to survive?

Conclusion: Releasing Dragons will let Gigas live

+

Premise: Giga were only fish in lake Premise: Sovkas now in lake Premise: Sovkas eat other fish Premise: Dragons eat Sovkas

Assumption: Dragons won't eat the Gigas Assumption: Dragons won't somehow jeopardize Gigas Assumption: 100 Dragons is sufficient





Premise-Therefore-Conclusion test

Tips for Identifying Conclusions and Premises

• Watch for trigger words that indicate a conclusion

• Watch for trigger words that indicate a premise

therefore, thus, hence, so, implies, indicates, consequently, as a result, clearly, accordingly, infer, conclude

since, because, for, due to, evidence, on the basis of, given that

• Beware of common argument structures

1. Premise, premise, . . . , conclusion

2. Conclusion, premise, premise . . .

3. Conclusion in the question stem




Common Argument Types (watch the entire video here)



Common Argument Types

3 Most Common Argument Types

• Cause and Effect

• Statistical

• Analogy





Cause and Effect

Conclusion: X causes Y

+

Premise: Event X occurs Premise: Event Y occurs

Assumption: X is the only possible cause of Y

A recent study reveals that the rate of obesity is higher among senior citizens who watch more than 8 hours of television per day than among senior citizens who watch fewer than 8 hours of television per day. Therefore, obesity among senior citizens is caused by watching more than 8 hours of television per day.

correlation ≠ causation

Weaken

• Something else causes Y

• Y causes X

• X and Y are coincidental

Strengthen

• More information

• Eliminate other causes of Y





Statistical

Conclusion: Something about entire population

+ Premise: Information from sample

Assumption: Sample represents entire population

In a recent survey, participants at a Republicans-only dance competition were given a questionnaire. Most of the respondents indicated that they enjoyed singing. Therefore, it can be concluded that most Republicans are outgoing people.

Weaken

• Sample not representative

• Conclusion doesn’t match stats

• Flaw in calculations

Strengthen

• Sample is representative





Analogy

Conclusion: Some other similarity exists

+

Premise: Similarity between X and Y Premise: Similarity between X and Y Premise: Similarity between X and Y

Assumption: Sharing some means sharing all

Country X is a democratic, tropical country with a population of 5 million, and Country Y is a democratic, tropical country with a population of 5 million. Since Country X is experiencing widespread crop failures, Country Y must be experiencing widespread crop failures as well.

Weaken

• Entities less similar

Strengthen

• Entities even more similar





Cause and Effect

Conclusion: X causes Y

+

Premise: Event X occurs Premise: Event Y occurs

Assumption: X is the only possible cause of Y

Weaken

• Something else causes Y • Y causes X • X and Y are coincidental

Strengthen

• More information • Eliminate other causes of Y

Statistical

Conclusion: Something about entire population

+ Premise: Information from sample

Assumption: Sample represents entire population

Weaken

• Sample not representative • Conclusion doesn’t match stats • Flaw in calculations

Strengthen

• Sample is representative

Analogy

Conclusion: Some other similarity exists

+

Premise: Similarity between X and Y Premise: Similarity between X and Y Premise: Similarity between X and Y

Assumption: Sharing some means sharing all

Weaken

• Entities less similar

Strengthen

• Entities even more similar



General Critical Reasoning Strategy (watch the entire video here)



Question Types

General Critical Reasoning Strategy

1. Weaken the Argument

2. Strengthen the Argument

3. Assumption

4. Conclusion/Inference

5. Method of Reasoning

6. Flawed Argument

7. Paradox

8. Evaluation




General Strategy

General Critical Reasoning Strategy

1. Read the question stem to determine the question type

2. Read the passage (argument) and focus on the required information for that question type

3. Check all answer choices




Weaken the Argument Questions (watch the entire video here)



Weaken the Argument Questions

Conclusion

Premise Premise Premise

Assumption Assumption +

(A) New Premise (B) New Premise (C) New Premise (D) New Premise (E) New Premise

Goal: Find the answer choice that, when added to the argument, undermines the conclusion the most.





General Strategy








Question stem examples

Which of the new premises hurts the argument the most?

• Which of the following, if true, most seriously weakens the argument above?

• Which of the following, if true, would cast the most serious doubt on the researcher’s conclusion?

• Which of the following, if true, most effectively challenges the conclusion that releasing 100 Dragonfish into Chilliwack Lake will allow the Gigafish in Chilliwack Lake to survive?

• Which of the following, if established, most seriously calls into question the argument above?

• Which of the following, if true, most seriously undermines the spokesperson’s position?





General Strategy








Weaken the Argument Strategy

1. Identify and summarize the conclusion

2. Identify and summarize the premises

3. Identify any assumptions

4. Check each answer choice while repeating conclusion


Does this weaken the conclusion that...?





Tips

- Undermining an unstated assumption

- Adding a new premise that hurts the conclusion

1. Look for common argument types (cause and effect, statistical, analogy)

2. Common ways to weaken an argument

3. “Weaken” does not necessarily mean “destroy”

4. Beware of answer choices that strengthen the argument

5. Do not try to disprove a premise

6. Goal: Weaken the extent to which the conclusion follows from the premises





Weaken the Argument Strategy






Example conclusion: Eating carrots improves one’s eyesight

Does this weaken the conclusion that...?




Practice Question

A program instituted in a particular state allows parents to prepay their children's future college tuition at current rates. The program then pays the tuition annually for the child at any of the state's public colleges in which the child enrolls. Parents should participate in the program as a means of decreasing the cost of their children's college education.

Which of the following, if true, is the most appropriate reason for parents not to participate in the program?

A. The parents are unsure about which public college in the state the child will attend.

B. The amount of money accumulated by putting the prepayment funds in an interest-bearing account today will be greater than the total cost of tuition for any of the public colleges when the child enrolls.

C. The annual cost of tuition at the state's public colleges is expected to increase at a faster rate than the annual increase in the cost of living.

D. Some of the state's public colleges are contemplating large increases in tuition next year.

E. The prepayment plan would not cover the cost of room and board at any of the state's public colleges.

This is a question from the GMAT® mini-test. GMAT® questions are the property of the Graduate Management Admission Council® and are used here with their permission.

Practice Question

A program instituted in a particular state allows parents to prepay their children's future college tuition at current rates. The program then pays the tuition annually for the child at any of the state's public colleges in which the child enrolls. Parents should participate in the program as a means of decreasing the cost of their children's college education.

Which of the following, if true, is the most appropriate reason for parents not to participate in the program?

P: Program: prepay tuition @ current rates

P: Program pays tuition later

C: Program is cheaper

A: Today’s cost less than future cost

A. The parents are unsure about which public college in the state the child will attend.

B. The amount of money accumulated by putting the prepayment funds in an interest-bearing account today will be greater than the total cost of tuition for any of the public colleges when the child enrolls.

C. The annual cost of tuition at the state's public colleges is expected to increase at a faster rate than the annual increase in the cost of living.

D. Some of the state's public colleges are contemplating large increases in tuition next year.

E. The prepayment plan would not cover the cost of room and board at any of the state's public colleges.




Practice Question

To attract members away from other fitness clubs in the city, FitnessTown recently launched a new marketing campaign in which each new member receives a free locker rental, free fitness consultations, and unlimited use of the tanning beds. FitnessTown’s marketing team claims that the campaign has been a huge success, since its membership has already increased 20 percent in the first two weeks of the campaign.

Which of the following, if true, would best help to refute the claim of FitnessTown’s marketing team?

A. Almost all of FitnessTown’s new members had never visited a fitness club before they were enticed by FitnessTown’s new campaign.

B. Most of FitnessTown’s new members do not intend to use the free services offered in the campaign.

C. FitnessTown’s investors hope to increase membership by 50 percent within the first month of the campaign.

D. FitnessTown’s new marketing campaign is identical to its previous marketing campaigns.

E. Studies show that people typically cancel their fitness club memberships within the first year.


Practice Question

To attract members away from other fitness clubs in the city, FitnessTown recently launched a new marketing campaign in which each new member receives a free locker rental, free fitness consultations, and unlimited use of the tanning beds. FitnessTown’s marketing team claims that the campaign has been a huge success, since its membership has already increased 20 percent in the first two weeks of the campaign.

Which of the following, if true, would best help to refute the claim of FitnessTown’s marketing team?

A. Almost all of FitnessTown’s new members had never visited a fitness club before they were enticed by FitnessTown’s new campaign.

B. Most of FitnessTown’s new members do not intend to use the free services offered in the campaign.

C. FitnessTown’s investors hope to increase membership by 50 percent within the first month of the campaign.

D. FitnessTown’s new marketing campaign is identical to its previous marketing campaigns.

E. Studies show that people typically cancel their fitness club memberships within the first year.

P: Campaign = locker, consult. & tanning

P: Membership up 20% in 2 wks

C: FitnessTown stole others’ members

A: membership increase means stolen

customers.




Strengthen the Argument Questions (watch the entire video here)



Conclusion




Goal: Find the answer choice that, when added to the argument, strengthens the conclusion the most.

Strengthen the Argument Questions (watch the entire video here)




Which of the new premises improves the argument the most?

Strengthen the Argument Questions

• Which of the following, if true, would provide the most support for the conclusion of the argument above?

• Which of the following statements, if true, most strengthens the author’s argument?

• Which of the following, if true, provides the best indication that Suki’s decision was logically sound?

• Which of the following, if true, most strongly supports the recommendation made by the argument?




Does this strengthen the conclusion that...?

Example conclusion: Antonio makes the world’s best spaghetti

Strengthen the Argument Strategy










Tips

• Look for common argument types (cause and effect, statistical, analogy)

• Common ways to strengthen an argument

• The goal is not to create a perfect argument

• Beware of answer choices that weaken the argument

• Watch out for answer choices that support a premise but not the conclusion


- Stating a previously-unstated assumption

- Supporting or elaborating on an existing premise

- Adding a new supporting premise

Bonnie must be great chess player

Avram is world-class sprinter Avram is great chess player Bonnie is world-class sprinter +

(A) Bonnie holds 100m world record (B) . (C) . (D) . (E) .





Does this strengthen the conclusion that...?

Strengthen the Argument Strategy









Practice Question

In the 12 years since the pretzel desalinization plant was built on the Polahoochi River, the salinity of the river has increased from 180 µS/cm to 911 µS/cm in the 10-mile stretch of river downstream from the plant. During the same 12-year period, researchers have observed a sharp decline in the average number of eggs laid by individual polafish, a species native to the Polahoochi River. Given this information, Dr. Kim hypothesizes that high salinity levels adversely affect the reproductive organs of the polafish.

Which of the following, if true, would most strengthen Dr. Kim’s hypothesis?

A. In the same state, many populations of polafish that are not downstream of pretzel desalinization plants have experienced a reduction in egg production.

B. Prior to the construction of the pretzel desalinization plant, the salinity of the 10-mile stretch of river downstream never exceeded 180 µS/cm.

C. Other species of fish in the same 10-mile stretch have experienced a sharp reduction in egg production.

D. In the past 12 years, the salinity of the tributaries flowing into the 10-mile stretch of river downstream from the plant has remained below 180 µS/cm, and the polafish living in these tributaries have not experienced any decline in egg production.

E. In other states, fish downstream from pretzel desalinization plants have experienced declines in egg production.


Practice Question

In the 12 years since the pretzel desalinization plant was built on the Polahoochi River, the salinity of the river has increased from 180 µS/cm to 911 µS/cm in the 10-mile stretch of river downstream from the plant. During the same 12-year period, researchers have observed a sharp decline in the average number of eggs laid by individual polafish, a species native to the Polahoochi River. Given this information, Dr. Kim hypothesizes that high salinity levels adversely affect the reproductive organs of the polafish.

Which of the following, if true, would most strengthen Dr. Kim’s hypothesis?

P: plant blt 12 yrs ago

P: downstream: salt

P: downstream: polafish eggs

C: salinity lowers polafish egg #s

A: salinity is only possible cause of

egg

A. In the same state, many populations of polafish that are not downstream of pretzel desalinization plants have experienced a reduction in egg production.

B. Prior to the construction of the pretzel desalinization plant, the salinity of the 10-mile stretch of river downstream never exceeded 180 µS/cm.

C. Other species of fish in the same 10-mile stretch have experienced a sharp reduction in egg production.

D. In the past 12 years, the salinity of the tributaries flowing into the 10-mile stretch of river downstream from the plant has remained below 180 µS/cm, and the polafish living in these tributaries have not experienced any decline in egg production.

E. In other states, fish downstream from pretzel desalinization plants have experienced declines in egg production.




Assumption Questions (watch the entire video here)



Conclusion



(A) Assumption (B) Assumption (C) Assumption (D) Assumption (E) Assumption

Goal: Find a necessary assumption

Assumption Questions (watch the entire video here)




Assumption Questions

• Which of the following is an assumption on which the argument depends?

• The scientist’s argument depends on the assumption that

• The conclusion above follows logically if which of the following is assumed?




Is this assumption necessary to draw the conclusion that...?

Assumption Question Strategy




4. Look for one of your assumptions among the answer choices

5. Check each answer choice against the conclusion


Example conclusion: Hotdogs are bad for one’s health







Want information that helps the conclusion

Want information that is necessary for the conclusion




Negation Technique


Basis: 1) An assumption is absolutely necessary for a conclusion to follow from the premises

2) Negating a necessary assumption will destroy the argument

Juan has been practicing tennis 3 hours each day for the past 2 years. Therefore, Juan will win the city championship next month.

C: J will win championship

P: J practicing 3hr/day for 2 yrs

+ A: Nothing stops championship A: J is eligible to play

A: It is not the case that J lives until championship

A: J lives until championship

P: J dies before championship

P: J dies before championship




Is this assumption necessary to draw the conclusion that...?

Assumption Question Strategy




4. Look for one of your assumptions among the answer choices

5. Check each answer choice against the conclusion

6. Apply Negation Technique:



Negate each answer choice and insert it into the argument. The negated answer choice that destroys the argument is the correct answer




Tips

• Look for common argument types (cause and effect, statistical, analogy)

• Look for shifts in language between premises and conclusion

• Remember that arguments can have any number of assumptions


Juan has been practicing tennis 3 hours each day for the past 2 years. Therefore, Juan will win the city championship next month.

C: J will win championship

P: J practicing 3hr/day for 2 mths

+

A: J lives until championship A: Nothing stops championship A: J is eligible to play




Practice Question

A. Investment firms should not restrict the ways in which portfolio managers manage their clients’ funds.

B. Portfolio managers can provide above-average returns for their corporate clients only by short selling stocks.

C. Short selling is a technique used primarily for corporate clients.

D. Portfolio managers often used short selling techniques to provide above-average returns for corporate clients.

E. Before the investment firm issued the new rules, portfolio managers were not permitted to short sell stocks.

A leading investment firm has issued new rules that prevent its portfolio managers from short selling stocks for their corporate clients. One portfolio manager has concluded that this restriction prevents portfolio managers from providing above-average investment returns for their corporate clients.

Which of the following is an assumption that would allow the portfolio manager’s conclusion to be properly drawn?


Practice Question

A. Investment firms should not restrict the ways in which portfolio managers manage their clients’ funds.

B. Portfolio managers can provide above-average returns for their corporate clients only by short selling stocks.

C. Short selling is a technique used primarily for corporate clients.

D. Portfolio managers often used short selling techniques to provide above-average returns for corporate clients.

E. Before the investment firm issued the new rules, portfolio managers were not permitted to short sell stocks.

A leading investment firm has issued new rules that prevent its portfolio managers from short selling stocks for their corporate clients. One portfolio manager has concluded that this restriction prevents portfolio managers from providing above-average investment returns for their corporate clients.

Which of the following is an assumption that would allow the portfolio manager’s conclusion to be properly drawn?

A: SS necessary to make big $

P: New rules prevent SS

C: Rules stop big $ for CC




Conclusion/Inference Questions (watch the entire video here)



?

Premise Premise Premise +

(A) Conclusion (B) Conclusion (C) Conclusion (D) Conclusion (E) Conclusion

Goal: Find conclusion that logically follows





Conclusion/Inference Questions

• The statements above, if true, most strongly support which of the following conclusions?

• If the statements above are true, which of the following must also be true on the basis of them?

• Which of the following hypotheses receives the strongest support from the given information?

• Which of the following can be logically inferred based on the statements above?

Identify something that must follow from the premises

Inference question = Conclusion question





For the past 3 days, all of Florida’s orange farms have experienced freezing temperatures. Therefore, the number of oranges harvested this year will be less than expected.

Typical Conclusion (in most GMAT questions)

Conclusion in a Conclusion question

• Conclusion is partially supported

For the past 3 days, the temperature at every Florida orange farm has not exceeded -5 degrees Celsius.

The statement above, if true, most strongly supports which of the following conclusions?

• Conclusion is guaranteed

(A) The number of oranges harvested this year will be less than expected.












(A) The orange harvest at some Florida farms will be less than expected.












(A) At least one orange will be damaged from the freezing temperatures.












(A) For the past 3 days, not one Florida orange farm has experienced temperatures above -5 degrees Celsius.












(A) During the past 3 days, at least one Florida orange farm has experienced temperatures lower than 40 degrees Celsius.




Must it be true that...?

Conclusion Question Strategy


2. Draw a conclusion that must follow

3. Look for your conclusion among the answer choices

4. Aggressively eliminate incorrect answers

5. Apply a version of the Negation Technique:



The negated conclusion that contradicts the premises the most is probably the correct answer.




Tips

1. Do not stray too far from the premises

2. Look for a rewording of a premise

P: Kyle enjoys chocolate

P: Rome is the capital of Italy


Example

C: ?

What conclusion can be drawn using every premise?




Tips



P: Kyle enjoys chocolate

P: Rome is the capital of Italy


Example

C: The capital of Italy is Rome




Tips



3. Conclusions need not involve every premise

4. Do not inject assumptions into the argument

5. Beware of answer choices that introduce new ideas/words

6. Beware of answer choices where the strength of the language does not match the strength of the language in the premises




Practice Question

While studying Emperor Penguins in Antarctica during the coldest 3 months of the year, researchers observed that several of the penguins died. The researchers also discovered that the death rate among the larger penguins was greater than the death rate among the smaller penguins. However, the researchers’ conclusion that size was a determinant in these deaths is probably mistaken, since smaller penguins are typically younger than larger ones.

If the above statements are true, which of the following can be inferred?

A. Among Emperor Penguins of the same age, the smaller penguins have a greater survival rate over a 3-month period than the larger penguins do.

B. Among the Emperor Penguins that survived the 3-month period, there is probably no relationship between age and size.

C. Among Emperor Penguins of the same age, a difference in size may not indicate a difference in chances of survival over a 3-month period.

D. Temperature does not play a role in the death rate among Emperor Penguins over a 3-month period.

E. Among Emperor Penguins of the same size, age is a determinant in the survival rate over a 3-month period.


Practice Question

While studying Emperor Penguins in Antarctica during the coldest 3 months of the year, researchers observed that several of the penguins died. The researchers also discovered that the death rate among the larger penguins was greater than the death rate among the smaller penguins. However, the researchers’ conclusion that size was a determinant in these deaths is probably mistaken, since smaller penguins are typically younger than larger ones.

If the above statements are true, which of the following can be inferred?

P: P’s died during 3 coldest mnths

P: Larger P’s more likely to die

P: Resrchrs conclude size a factor

P: Size probably not a factor

P: Smaller P’s typically younger

A. Among Emperor Penguins of the same age, the smaller penguins have a greater survival rate over a 3-month period than the larger penguins do.

B. Among the Emperor Penguins that survived the 3-month period, there is probably no relationship between age and size.

C. Among Emperor Penguins of the same age, a difference in size may not indicate a difference in chances of survival over a 3-month period.

D. Temperature does not play a role in the death rate among Emperor Penguins over a 3-month period.

E. Among Emperor Penguins of the same size, age is a determinant in the survival rate over a 3-month period.




Structure Questions (watch the entire video here)



Structure Questions

• Test your understanding of the argumentative strategies employed in an argument

• 3 types of Structure Questions:

- Method of Reasoning

- Boldface

- Parallel Argument




(A) Description of argument (B) Description of argument (C) Description of argument (D) Description of argument (E) Description of argument

Goal: Find the best description of the author’s argumentative strategy.

Method of Reasoning questions

Conclusion






Question stem examples for Method of Reasoning questions

Explain how the author presents his/her argument

Structure Questions

• The author’s point is made by which method of reasoning?

• Which of the following strategies does Dr. Kwan use to defend his position?

• In the passage, the author develops the argument by ___

• The reporter challenges the spokesperson’s position by doing which of the following?




Examples of answer choices for Method of Reasoning questions

Structure Questions

• The argument arrives at its conclusion by demonstrating the inherent problems with alternative conclusions.

• The author offers a new definition of a term that is central to an opposing argument.

• The argument employs circular reasoning by assuming that which it is trying to prove.

The answer choices are typically generic




Strategy for tackling Method of Reasoning questions

1. Read the passage

2. For each sentence, ask, “What role does this play in the argument?”

3. Identify and summarize the conclusion and premises

4. Use generic language to describe the method of reasoning to yourself

5. Look for your description among the answer choices





(A) Role played by boldfaced portion(s) (B) Role played by boldfaced portion(s) (C) Role played by boldfaced portion(s) (D) Role played by boldfaced portion(s) (E) Role played by boldfaced portion(s)

Goal: Find the best description of the role(s) played

Boldface questions

Conclusion






Question stem examples for Boldface questions

The passage contains bolded text

Structure Questions

• In the above argument, the portion in boldface plays which of the following roles?

• In the researcher’s argument, the two portions in boldface play which of the following roles?


In the above argument, the portion in boldface plays which of the following roles?




Strategy for tackling Boldface questions

1. Read the passage

2. For each boldfaced portion, ask, “What role does this play in the argument?”


4. Use generic language to describe the roles played by the boldfaced portion(s)

5. Find the answer choice that most closely matches yours





Tips for Boldface questions

1. Look for common roles:

2. Consider how the second bolded part is related to first bolded part

3. Beware of answer choices that are half right and half wrong

Structure Questions

- Concluding

- Summarizing

- Contradicting

- Providing supporting evidence

- Providing an example

- Providing a counterexample

- Generalizing




Structure Questions

(A) Complete argument (B) Complete argument (C) Complete argument (D) Complete argument (E) Complete argument

Goal: Find the argument that employs the most similar argumentative strategy.

Parallel Argument questions

Conclusion






Structure Questions

Question stem examples for Parallel Argument questions

Find the argument most like the original

• Which of the following arguments exhibits a pattern of reasoning most similar to the pattern of reasoning exhibited in the argument above?

• Which of the following is most like the argument above in its logical structure?

• The pattern of reasoning displayed above is most closely paralleled in which of the following?




Structure Questions

Strategy for tackling Parallel Argument questions


2. Use generic language to describe the method of reasoning to yourself before checking the answer choices

3. Look for an argument with same structure





Structure Questions

Tips for Parallel Argument questions

1. Beware of answer choices with same subject matter

2. Questions are time-consuming check your time




Structure Questions

• Test your understanding of the argumentative strategies employed in an argument

• 3 types of Structure Questions:

- Method of Reasoning

- Boldfaced

- Parallel Argument




Practice Question

ABC Widget’s plan to decrease employee salaries by 15% makes sense. Granted, the reduced salaries will place a financial burden on many employees. But, if the company does not decrease employee salaries, it will not have enough money to stay in business, and everyone at the company will lose his or her job.

The passage employs which of the following argumentative strategies?

A. It explains why the alternative course of action would not be subject to the objections raised against the proposed course of action.

B. It describes an ideal situation by way of a situation that is less than ideal.

C. It indirectly arrives at its conclusion by providing grounds to reject an alternative approach.

D. It extrapolates the perceived outcome of the proposed plan in order to criticize the alternative course of action.

E. It employs circular reasoning by assuming that which it is trying to prove.


Practice Question

A. It explains why the alternative course of action would not be subject to the objections raised against the proposed course of action.

B. It describes an ideal situation by way of a situation that is less than ideal.

C. It indirectly arrives at its conclusion by providing grounds to reject an alternative approach.

D. It extrapolates the perceived outcome of the proposed plan in order to criticize the alternative course of action.

E. It employs circular reasoning by assuming that which it is trying to prove.

P: 15% cut will hurt many

P: No cut no jobs

C: 15% cut makes sense

Not doing X is much worse than doing X. So, we should do X.

ABC Widget’s plan to decrease employee salaries by 15% makes sense. Granted, the reduced salaries will place a financial burden on many employees. But, if the company does not decrease employee salaries, it will not have enough money to stay in business, and everyone at the company will lose his or her job.

The passage employs which of the following argumentative strategies?




Practice Question

Fred: Columbus was a great explorer because he held on to his conviction that the Earth was round in the face of overwhelming opposition.

Stan: The mark of a great explorer is bravery not the adherence to a conviction. Besides, the concept of a round Earth was widely accepted in the fifteenth century, when Columbus was looking for someone to fund his voyage.

In Stan’s response, the two boldface portions play which of the following

roles?

A. The first presents an alternative conclusion; the second provides evidence in support of that conclusion.

B. The first rejects the criterion on which Fred’s argument is based; the second disputes a specific claim.

C. The first presents an alternative criterion; the second describes a premise on which Stan’s conclusion relies.

D. The first elaborates on Fred’s criterion; the second presents a premise on which Stan’s conclusion relies.

E. The first reveals a contradiction in Fred’s argument; the second resolves that contradiction.


Practice Question

Fred: Columbus was a great explorer because he held on to his conviction that the Earth was round in the face of overwhelming opposition.

Stan: The mark of a great explorer is bravery not the adherence to a conviction. Besides, the concept of a round Earth was widely accepted in the fifteenth century, when Columbus was looking for someone to fund his voyage.

In Stan’s response, the two boldface portions play which of the following

roles?

A. The first presents an alternative conclusion; the second provides evidence in support of that conclusion.

B. The first rejects the criterion on which Fred’s argument is based; the second disputes a specific claim.

C. The first presents an alternative criterion; the second describes a premise on which Stan’s conclusion relies.

D. The first elaborates on Fred’s criterion; the second presents a premise on which Stan’s conclusion relies.

E. The first reveals a contradiction in Fred’s argument; the second resolves that contradiction.

Fred

P: Conviction despite opposition

C: Columbus great explorer

Stan

1st: Great = bravery not conviction

2nd: Round earth known

Stan

1st: Refutes standard

2nd: Calls statement false




Practice Question

In Townville, most smokers play tennis, and most nonsmokers do not play tennis. Therefore, in Townville, most tennis players smoke.

Which of the following exhibits a pattern of flawed reasoning most similar to that in the argument above?

A. In Townville, most Lions Club members were born in Townville, and most of the residents who are not Lions Club members were not born in Townville. Therefore, most of the residents who were born in Townville are Lions Club members.

B. In Townville, most of the people who live west of Main Street own a GPS, and most of the people who own a GPS live east of Main street. Therefore, most of the people in Townville own a GPS.

C. In Townville, most cat owners own exactly one dog, and most dog owners own more than one dog. Therefore, most of the people in Townville who own more than one dog do not own any cats.

D. In Townville, most tennis players play golf, but not every golfer plays tennis. Therefore, in Townville, there are more tennis players than golfers.

E. In Townville, most of the houses are painted red, and most of the houses have a pool. Therefore, in Townville, most of the houses are painted red and have a pool.


Practice Question

In Townville, most smokers play tennis, and most nonsmokers do not play tennis. Therefore, in Townville, most tennis players smoke.

Which of the following exhibits a pattern of flawed reasoning most similar to that in the argument above?

P: S T

P: ~S ~T

C: T S

A. In Townville, most Lions Club members were born in Townville, and most of the residents who are not Lions Club members were not born in Townville. Therefore, most of the residents who were born in Townville are Lions Club members.

B. In Townville, most of the people who live west of Main Street own a GPS, and most of the people who own a GPS live east of Main street. Therefore, most of the people in Townville own a GPS.

C. In Townville, most cat owners own exactly one dog, and most dog owners own more than one dog. Therefore, most of the people in Townville who own more than one dog do not own any cats.

D. In Townville, most tennis players play golf, but not every golfer plays tennis. Therefore, in Townville, there are more tennis players than golfers.

E. In Townville, most of the houses are painted red, and most of the houses have a pool. Therefore, in Townville, most of the houses are painted red and have a pool.




Flawed Argument Questions (watch the entire video here)



(A) Main problem (B) Main problem (C) Main problem (D) Main problem (E) Main problem

Goal: Find the argument’s primary flaw

Flawed Conclusion



Flawed Argument Questions (watch the entire video here)




Identify the main problem with the argument

Flawed Argument Questions

• Which of the following identifies the most serious logical flaw in the argument above?

• Which one of the following best identifies the error in reasoning made in the passage?

• The argument is vulnerable to criticism on which one of the following grounds?

• The reasoning in the argument is not sound because it fails to establish that ___





2. Identify any unstated assumptions

3. Determine the primary flaw

4. Look for your answer among the answer choices



Strategy




Common Flaws


While studying the reading levels of elementary students, researchers discovered that, on average, the longer a child’s foot, the higher his/her reading level. Therefore, foot growth increases one’s reading level.

• Confusing causation with correlation




Common Flaws


• Confusing numbers with rates


Last year, 10 people were murdered in Happyton, and 100 people were murdered in Killington. Therefore, it is much safer to live in Happyton than in Killington




Common Flaws



• Conclusion mismatch


Last year, hundreds of postal workers in Maltania suffered back injuries from carrying heavy packages at the sorting stations. To help reduce these injuries, the government should introduce a law that prohibits people from mailing packages that are over 3 feet in length.

- Watch out for new words in the conclusion




Common Flaws





• Extreme conclusion


In some countries, raising the minimum wage can help boost the economy. So, if Maltania raises its minimum wage, its economy will improve.




Common Flaws






• Mistaking necessary for sufficient


In order to be a great science teacher, one must have a deep understanding of biology. Since Terrence has a deep understanding of biology, he must be a great science teacher.




Common Flaws







• Guilty by association


Sharon, Margaret and Rena are tall, Hoopton High students who play basketball. Since Maureen is a tall, Hoopton High student, she must play basketball.




Common Flaws







• Guilty by association

• Unrepresentative sample


Recently, a questionnaire was given to the inhabitants of Capton, Maltania’s capital city. 83% of respondents said they own one or more horses. Therefore, we can conclude that most people in Maltania own one or more horses.






2. Identify any unstated assumptions

3. Determine the primary flaw

4. Look for your description among the answer choices


Strategy




Practice Question

A. The author assumes that the only varieties of jabberwocky are longhaired and shorthaired.

B. The author does not consider what proportion of all cases of jimmylegs involves longhaired jabberwockies.

C. The author calls into question the authenticity of the WJS data without providing any data to the contrary.

D. The author takes no account of the relative frequency of longhaired jabberwockies within the jabberwocky population.

E. The author limits the argument to an unnecessarily restrictive subset of criteria before drawing a general conclusion.

Jimmylegs, a disorder of the metatarsals, affects only jabberwockies. A popular belief contends that the longhaired variety of the jabberwocky is more predisposed to contract jimmylegs than are other varieties of jabberwocky. This, however, is clearly a myth, since data collected by the World Jabberwocky Society (WJS) indicate that, of all the jabberwockies that contract jimmylegs each year, the majority of the cases involve shorthaired jabberwockies.

Which of the following highlights the most serious flaw in the above argument?


Practice Question

A. The author assumes that the only varieties of jabberwocky are longhaired and shorthaired.

B. The author does not consider what proportion of all cases of jimmylegs involves longhaired jabberwockies.

C. The author calls into question the authenticity of the WJS data without providing any data to the contrary.

D. The author takes no account of the relative frequency of longhaired jabberwockies within the jabberwocky population.

E. The author limits the argument to an unnecessarily restrictive subset of criteria before drawing a general conclusion.

Jimmylegs, a disorder of the metatarsals, affects only jabberwockies. A popular belief contends that the longhaired variety of the jabberwocky is more predisposed to contract jimmylegs than are other varieties of jabberwocky. This, however, is clearly a myth, since data collected by the World Jabberwocky Society (WJS) indicate that, of all the jabberwockies that contract jimmylegs each year, the majority of the cases involve shorthaired jabberwockies.

Which of the following highlights the most serious flaw in the above argument?

A: Pop. breakdown supports conclusion

Flaw: We don’t know the population breakdown

P: J-legs = jabberwocky disorder

P: Belief: longhair predisposed to j-legs

P: Majority of cases are shorthair

C: Longhair not more predisposed




Paradox Questions (watch the entire video here)



Goal: Find premise that resolves the paradox

Paradox Questions

Conclusion

Premise Premise Premise +






Identify something that resolves the contradictory information

Paradox Questions

• The paradox described above is best resolved by which of the following?

• Which of the following, if true, most helps to resolve the apparent discrepancy described above?

• Which of the following, if true, best explains the paradoxical outcome of Dr. Doolittle's experiment?

• Which one of the following most helps to explain the apparent contradiction above?

• Which one of the following, if true, most helps to explain the difference in melting points?




Paradox Questions

Statistics show that the number of smokers in Maltania has steadily decreased over the past 10 years. However, during the same 10 years, the total amount of tobacco sold by Maltanian tobacco farmers has increased.

Which of the following, if true, most helps to resolve the apparent discrepancy described above?

• Looking for an “aha” premise

• Not testing ability to deconstruct arguments

• Several explanations:

- Farmers exporting to other markets

- Big increase in tobacco chewers

- and more . . .




Does this explain why...?

Paradox Question strategy

1. Identify the contradictory premises

2. Explain the paradox to yourself

3. Check the answer choices while reminding yourself of the paradox


Paradox Questions

e.g., More tobacco sold despite fewer smokers




Tips

• Keywords: yet, however, surprisingly, nonetheless, paradoxically

• Unable to identify paradox

Paradox Questions

solution unlikely

reread passage or guess and move on

• Beware of answer choices that have opposite effect

Statistics show that the number of smokers in Maltania has steadily decreased over the past 10 years. However, during the same 10 years, the total amount of tobacco sold by Maltanian tobacco farmers has increased.

Which of the following, if true, most helps to resolve the apparent discrepancy described above?

(A) The Maltanian government has introduced stop-smoking programs across the country.




Practice Question

Among the mechanics at Joe’s Garage, the senior mechanics are the most adept at diagnosing engine problems. However, the itemized bills for engine repairs made during the past four years suggest otherwise. From the bills, we see that, on average, the senior mechanics took 29 minutes to correctly diagnose an engine problem, while the junior mechanics took only 22 minutes.

Which of the following, if true, most helps to resolve the apparent paradox?

A. At Joe’s Garage, mechanics with more than three years of experience are called senior mechanics.

B. Some of the junior mechanics had experience diagnosing engine problems before they began working at Joe’s Garage.

C. At Joe’s Garage, the manager typically assigns to the junior mechanics engine problems that he expects will be relatively easy to diagnose.

D. During the past 4 years, most of the senior mechanics left Joe’s Garage to open their own garages.

E. Mechanics who are more adept at diagnosing engine problems are faster

at completing the required repair.


Practice Question

Among the mechanics at Joe’s Garage, the senior mechanics are the most adept at diagnosing engine problems. However, the itemized bills for engine repairs made during the past four years suggest otherwise. From the bills, we see that, on average, the senior mechanics took 29 minutes to correctly diagnose an engine problem, while the junior mechanics took only 22 minutes.

Which of the following, if true, most helps to resolve the apparent paradox?

P: Sr. mechs best at diagnosing

P: 29 min for sr. mechs, and .22 min for jr. mechs

Paradox: Sr. mechanics take longer despite their superior diagnostic skills.

A. At Joe’s Garage, mechanics with more than three years of experience are called senior mechanics.

B. Some of the junior mechanics had experience diagnosing engine problems before they began working at Joe’s Garage.

C. At Joe’s Garage, the manager typically assigns to the junior mechanics engine problems that he expects will be relatively easy to diagnose.

D. During the past 4 years, most of the senior mechanics left Joe’s Garage to open their own garages.

E. Mechanics who are more adept at diagnosing engine problems are faster

at completing the required repair.




Evaluate the Conclusion Questions (watch the entire video here)



(A) Question (B) Question (C) Question (D) Question (E) Question

Conclusion



Evaluate the Conclusion Questions

Goal: Find the question that, when answered, best helps to evaluate the conclusion.





Which of the following would be most relevant to investigate in order to evaluate the researcher’s conclusion?


Conclusion: Wolves not responsible for population decrease.

A) In what season was the wolf pack relocated to Bilford Island?

B) What proportion of rabbits have died from the myxoma virus?

C) Did the wolf pack introduce the myxoma virus to Bilford Island?

D) . . . Goal: Find the question that, when answered,

helps evaluate the conclusion





Identify a question that would help gauge the strength of the conclusion


• Knowing which of the following would be most useful in evaluating the argument?

• Which of the following would be most relevant to investigate in order to evaluate the researcher’s conclusion?

• Clarification of which of the following issues would be most important to evaluating the spokesperson’s position?




Strategy



3. Check the answer choices by providing an answer to each question and relating it to the conclusion


Evaluate the Conclusion Questions (watch the entire video here)




Goal: Find the question that, when answered, helps evaluate the conclusion.










Which of the following would be most relevant to investigate to evaluate the researcher’s conclusion?

Summer










Winter











43%

Winter












43%

Winter

Yes












43%

Winter

No





Strategy








Practice Question

Professor Gelding: The belief that our planet will experience a wave of extreme weather events over the next 100 years is nonsense. There is no evidence to support that the rate of extreme weather events is increasing.

Professor Brink: To see where you are mistaken, you need only examine the data concerning Category 5 hurricanes in the Gulf of Mexico that made landfall in the past 100 years. In the first 50 years, there were only 6 such hurricanes, but in the last 50 years, there were 19 such hurricanes.

Clarification of which of the following issues would be most important to an evaluation of Professor Brink’s conclusion?

A. Does the rate at which Category 5 hurricanes make landfall affect the rate of other extreme weather events?

B. Do the statistics concerning Category 5 hurricanes that made landfall represent extreme weather events in the Gulf of Mexico?

C. During the last 100 years, what percent of hurricanes made landfall?

D. How many extreme weather events occurred in the past 100 years?

E. Do the Category 5 hurricanes in the Gulf of Mexico that made landfall in the past 100 years represent extreme weather events in general?


Practice Question

A. Does the rate at which Category 5 hurricanes make landfall affect the rate of other extreme weather events?

B. Do the statistics concerning Category 5 hurricanes that made landfall represent extreme weather events in the Gulf of Mexico?

C. During the last 100 years, what percent of hurricanes made landfall?

D. How many extreme weather events occurred in the past 100 years?

E. Do the Category 5 hurricanes in the Gulf of Mexico that made landfall in the past 100 years represent extreme weather events in general?

A: hurricane rate characterizes extreme weather rate

P: 1st 50 yrs: 6 hurricanes

P: 2nd 50 yrs: 19 hurricanes

C: EW rate is increasing

Professor Gelding: The belief that our planet will experience a wave of extreme weather events over the next 100 years is nonsense. There is no evidence to support that the rate of extreme weather events is increasing.

Professor Brink: To see where you are mistaken, you need only examine the data concerning Category 5 hurricanes in the Gulf of Mexico that made landfall in the past 100 years. In the first 50 years, there were only 6 such hurricanes, but in the last 50 years, there were 19 such hurricanes.

Clarification of which of the following issues would be most important to an evaluation of Professor Brink’s conclusion?




Miscellaneous Tips (watch the entire video here)



Miscellaneous Tips

• Question type frequencies

• GMAT words

• EXCEPT questions

• Being aggressive




Question type frequencies

Miscellaneous Tips



3. Assumption



6. Flawed Argument

7. Evaluation

8. Paradox




Question type frequencies

Miscellaneous Tips



3. Assumption



6. Flawed Argument

7. Evaluation

8. Paradox

¾+




Miscellaneous Tips

GMAT words

Everybody likes ice cream = a lot of people like ice cream

= most people like ice cream

Common usage

Everybody likes ice cream = every person likes ice cream

GMAT usage




Miscellaneous Tips

GMAT words

• Read words in their strongest, most literal sense

all, none, everyone, no one, always, never, each every, anywhere, nowhere

• Some: 1 or more

Some Gigacorp employees are college graduates.

Some countries in Europe are named Italy.

Some of Earth’s oceans contain salt water

• Most: More than 50%

Most of Earth’s oceans contain salt water




Miscellaneous Tips

EXCEPT questions

Today, Gary did not arrive at the office until 11am. Therefore Gary will be fired.

Each of the following, if true, weakens the conclusion above EXCEPT

• Does not mean “strengthen” the conclusion




Miscellaneous Tips

EXCEPT questions

Each of the following people is a former President of the United States EXCEPT

If the person is a former US president eliminate it.

(A) Abraham Lincoln

(B) George Washington

(C) Bugs Bunny

(D) Jimmy Carter

(E) George Bush




Miscellaneous Tips

EXCEPT questions

Today, Gary did not arrive at the office until 11am. Therefore Gary will be fired.

Each of the following, if true, weakens the conclusion above EXCEPT

If it weakens the conclusion, eliminate it.

(A) Work begins at noon

(B) Gary is self employed

(C) Gary likes ice cream




Miscellaneous Tips

Being aggressive

• Critical reasoning questions can be time consuming

• Students get lost in the answer choices

• Be aggressive!

“What if I eliminate all answer choices?”

• This will not happen often

• You will have earned time to recheck answer choices

Look for reasons to reject answer choices




Miscellaneous Tips

• Question type frequencies

• GMAT words

• EXCEPT questions

• Being aggressive




Practice Question

For decades, countries have measured wheat field productivity using the Wheat Field Productivity Index (WFPI), which is equal to the average number of pounds of grain harvested per acre of wheat. In 2005, Maltania’s WFPI was 60 pounds per acre more than Italy’s WFPI. In 2006, Maltania’s WFPI was 75 pounds per acre more than Italy’s. Therefore, Maltania’s wheat field productivity must have increased during that period.

Which of the following, if true, provides the strongest support for the conclusion above?

A. Between 2005 and 2006, the number of acres of wheat planted in both Maltania and Italy increased at the same rate.

B. In 2006, Maltania received 20% more sunshine than usual.

C. Between 2005 and 2006, Italy’s wheat field productivity decreased by 10 pounds per acre.

D. In 2006, Italy experienced its worst drought in decades.

E. In 2006, Maltania began subsidizing all of its wheat farmers.


Practice Question

P: WFPI = ave lbs wheat/acre

P: 2005: Maltania’s WFPI 60 more than Italy’s

P: 2006: Maltania’s WFPI 75 more than Italy’s

C: Maltania’s WFPI

A. Between 2005 and 2006, the number of acres of wheat planted in both Maltania and Italy increased at the same rate.

B. In 2006, Maltania received 20% more sunshine than usual.

C. Between 2005 and 2006, Italy’s wheat field productivity decreased by 10 pounds per acre.

D. In 2006, Italy experienced its worst drought in decades.

E. In 2006, Maltania began subsidizing all of its wheat farmers.

For decades, countries have measured wheat field productivity using the Wheat Field Productivity Index (WFPI), which is equal to the average number of pounds of grain harvested per acre of wheat. In 2005, Maltania’s WFPI was 60 pounds per acre more than Italy’s WFPI. In 2006, Maltania’s WFPI was 75 pounds per acre more than Italy’s. Therefore, Maltania’s wheat field productivity must have increased during that period.

Which of the following, if true, provides the strongest support for the conclusion above?




Practice Question

All of Pedro’s friends say they know someone who is a licensed circus clown. Pedro does not know any licensed circus clowns, and he is not unique among his friends in this respect.

If the above statements are true, which of the following must also be true?

A. Some of Pedro’s friends are lying.

B. Most licensed circus clowns lie about their profession.

C. Some of Pedro’s friends have friends that Pedro is not friends with.

D. Pedro is a licensed circus clown.

E. All of Pedro’s friends know the same licensed circus clown.


Practice Question

All of Pedro’s friends say they know someone who is a licensed circus clown. Pedro does not know any licensed circus clowns, and he is not unique among his friends in this respect.

If the above statements are true, which of the following must also be true?

A. Some of Pedro’s friends are lying.

B. Most licensed circus clowns lie about their profession.

C. Some of Pedro’s friends have friends that Pedro is not friends with.

D. Pedro is a licensed circus clown.

E. All of Pedro’s friends know the same licensed circus clown.

P: All friends SAY they know a C

P: Pedro knows zero Cs

P: Some friends don’t know a C




Practice Question

Reporter: The number of foreigners working at US ski resorts was lower last year than it had been in previous years. Last year, several ski resorts hired more local residents than they had hired in previous years, so it is likely that the reduced number of foreign workers at US ski resorts last year was due to the decreased demand for their services.

Which of the following, if true, most seriously undermines the reporter’s argument?

A. All foreigners who received work visas for last year’s ski season were able to find work at US ski resorts.

B. The average wait time to receive a US work visa has decreased substantially over the past three years.

C. The number of ski resorts that hired foreigners last year was the same as in previous years.

D. Foreigners can work for more than one ski resort in any given year.

E. Recent changes to US immigration laws drastically decreased the total number of work visas issued for last year.


Practice Question

Reporter: The number of foreigners working at US ski resorts was lower last year than it had been in previous years. Last year, several ski resorts hired more local residents than they had hired in previous years, so it is likely that the reduced number of foreign workers at US ski resorts last year was due to the decreased demand for their services.

Which of the following, if true, most seriously undermines the reporter’s argument?

A. All foreigners who received work visas for last year’s ski season were able to find work at US ski resorts.

B. The average wait time to receive a US work visa has decreased substantially over the past three years.

C. The number of ski resorts that hired foreigners last year was the same as in previous years.

D. Foreigners can work for more than one ski resort in any given year.

E. Recent changes to US immigration laws drastically decreased the total number of work visas issued for last year.

A: Nothing else caused decrease

A: Fewer foreign workers did not cause increase in locals hired

P: # foreign wrkrs lower last yr

P: More locals hired last yr

C: local employees caused foreign employees




Practice Question

After a plague of locusts attacked every crop in Baker County, Kevin Kevinson claimed that the severity of damage to his crops was due to the fish-based fertilizer he applied to his fields before planting.

Which of the following investigations is most likely to yield significant information that would help evaluate Kevin’s argument?

A. Comparing the value of Kevin’s crop damage to the average value of the crop damage at farms where fish-based fertilizer was not applied to the fields before planting

B. Determining the extent to which fish-based fertilizer increases crop yield

C. Comparing the long-term effects of Kevin’s crop damage to the long-term effects of other crop damage in Baker County

D. Comparing the severity of crop damage at Kevin’s farm with the crop damage at agriculturally similar Baker County farms where fish-based fertilizer was not applied to fields before planting

E. Determining the percentage of Baker County farms that applied fish-based fertilizer to their fields before planting


A. Comparing the value of Kevin’s crop damage to the average value of the crop damage at farms where fish-based fertilizer was not applied to the fields before planting

B. Determining the extent to which fish-based fertilizer increases crop yield

C. Comparing the long-term effects of Kevin’s crop damage to the long-term effects of other crop damage in Baker County

D. Comparing the severity of crop damage at Kevin’s farm with the crop damage at agriculturally similar Baker County farms where fish-based fertilizer was not applied to fields before planting

E. Determining the percentage of Baker County farms that applied fish-based fertilizer to their fields before planting

Practice Question

After a plague of locusts attacked every crop in Baker County, Kevin Kevinson claimed that the severity of damage to his crops was due to the fish-based fertilizer he applied to his fields before planting.

Which of the following investigations is most likely to yield significant information that would help evaluate Kevin’s argument?

P: Locusts hit all crops

P: Kevin applied FBF to crops

C: FBF caused severity

A: Nothing else caused the severity




Practice Question

Ayla is taller than Elan, and Brek is the same height as Diego. Since Chayna is shorter than Diego, it follows that Ayla is taller than Chayna.

Each of the following, when added to the argument as an additional premise, makes the argument logically correct EXCEPT:

A. Diego is shorter than Elan.

B. Ayla and Diego are the same height.

C. Brek is taller than Elan.

D. Elan and Chayna are the same height.

E. Brek is shorter than Ayla.


Practice Question

A. Diego is shorter than Elan.

B. Ayla and Diego are the same height.

C. Brek is taller than Elan.

D. Elan and Chayna are the same height.

E. Brek is shorter than Ayla.

If it makes the argument correct, eliminate it.

A

C

Premises:

Conclusion:

+ B=D

C

A

E

Ayla is taller than Elan, and Brek is the same height as Diego. Since Chayna is shorter than Diego, it follows that Ayla is taller than Chayna.

Each of the following, when added to the argument as an additional premise, makes the argument logically correct EXCEPT:




Practice Question

A. In the past 7 years, the CPT for king crabs has decreased by 50%.

B. 8 years ago, commercial crab-fishing boats began using high-tech sonar equipment that enables them to locate crabs with much greater accuracy.

C. 9 years ago, a deadly species of sea lice drove many crab species to near extinction.

D. In the past 10 years, the number of commercial crab traps set each year has remained relatively constant.

E. In the past 10 years, the worldwide price of snow crabs has more than doubled.

To estimate changes in crab populations, biologists monitor what is known as “crabs per trap” (CPT). The CPT is the average number of crabs that commercial crab fishermen catch per crab trap. Since the current CPT for snow crabs is the same as it was 10 years ago, biologists conclude that today’s snow crab population is approximately the same as it was 10 years ago.

Which of the following, if true, most seriously weakens the argument?


Practice Question

A. In the past 7 years, the CPT for king crabs has decreased by 50%.

B. 8 years ago, commercial crab-fishing boats began using high-tech sonar equipment that enables them to locate crabs with much greater accuracy.

C. 9 years ago, a deadly species of sea lice drove many crab species to near extinction.

D. In the past 10 years, the number of commercial crab traps set each year has remained relatively constant.

E. In the past 10 years, the worldwide price of snow crabs has more than doubled.

To estimate changes in crab populations, biologists monitor what is known as “crabs per trap” (CPT). The CPT is the average number of crabs that commercial crab fishermen catch per crab trap. Since the current CPT for snow crabs is the same as it was 10 years ago, biologists conclude that today’s snow crab population is approximately the same as it was 10 years ago.

Which of the following, if true, most seriously weakens the argument?

P: CPT = ave # crabs/trap

P: CPT now = 10 yrs ago

C: SC pop. ≈ 10 yrs ago

A: CPT reflects pop.




Practice Question

Identical twins have livers that are genetically identical. Scientists recently discovered that when one twin has hepachrinosis, a debilitating liver disease, the caudate lobe of the affected twin’s liver is significantly smaller than the caudate lobe of the unaffected twin’s liver. No such difference is found when neither twin has hepachrinosis. From this information, it can be concluded that hepachrinosis is caused by diminished liver capacity.

Which of the following is an assumption required by the argument?

A. Many diseases are caused by diminished organ capacity.

B. The caudate lobe of a healthy identical twin is the same size as the caudate lobe of a healthy person who is not an identical twin.

C. When two identical twins both suffer from hepachrinosis, their caudate lobes are the same size.

D. The relative smallness of the caudate lobe of an affected person is not the result of medications used in the treatment of hepachrinosis.

E. People who have an identical twin are no more likely to contract hepachrinosis than people who do not have an identical twin.


Practice Question

Identical twins have livers that are genetically identical. Scientists recently discovered that when one twin has hepachrinosis, a debilitating liver disease, the caudate lobe of the affected twin’s liver is significantly smaller than the caudate lobe of the unaffected twin’s liver. No such difference is found when neither twin has hepachrinosis. From this information, it can be concluded that hepachrinosis is caused by diminished liver capacity.

Which of the following is an assumption required by the argument?

A. Many diseases are caused by diminished organ capacity.

B. The caudate lobe of a healthy identical twin is the same size as the caudate lobe of a healthy person who is not an identical twin.

C. When two identical twins both suffer from hepachrinosis, their caudate lobes are the same size.

D. The relative smallness of the caudate lobe of an affected person is not the result of medications used in the treatment of hepachrinosis.

E. People who have an identical twin are no more likely to contract hepachrinosis than people who do not have an identical twin.

P: Twins have = livers

P: Lobe of affected twin is smaller

P: Lobes of unaffected twins are =

C: Small lobe causes H

A: nothing else causes H




Practice Question

On average, when 100 non-pregnant women take the Pregunda home pregnancy test, 10 of them will test positive. That is, the test will indicate that the women are pregnant. Conversely, when 100 pregnant women take the Pregunda home pregnancy test, 99 of them will test positive. Therefore, if a group of women take the Pregunda home pregnancy test, the vast majority of those who test positive will be pregnant.

The above argument is flawed primarily because it

A. does not take into consideration the test’s margin of error

B. suggests that non-pregnant women are more likely to test positive than pregnant women are

C. presupposes the proportion of pregnant women in the group

D. assumes that the test’s accuracy is not affected by other factors

E. ignores the fact that women who do not test positive may be pregnant


Practice Question

A. does not take into consideration the test’s margin of error

B. suggests that non-pregnant women are more likely to test positive than pregnant women are

C. presupposes the proportion of pregnant women in the group

D. assumes that the test’s accuracy is not affected by other factors

E. ignores the fact that women who do not test positive may be pregnant

On average, when 100 non-pregnant women take the Pregunda home pregnancy test, 10 of them will test positive. That is, the test will indicate that the women are pregnant. Conversely, when 100 pregnant women take the Pregunda home pregnancy test, 99 of them will test positive. Therefore, if a group of women take the Pregunda home pregnancy test, the vast majority of those who test positive will be pregnant.

The above argument is flawed primarily because it

A: Test accuracy is constant

P: 10% of NP test positive

P: 99% of P test positive

C: Group majority of positive are pregnant




Practice Question

Jesse: The H1 vaccine prevents people from contracting thramboxia, a disease that can cause short-term paralysis. While thramboxia is an unpleasant disease with paralysis lasting up to 3 months, the H1 vaccine is not worth getting since hundreds of people die each year from the H1 vaccination.

Harjit: But thousands of people die each year as a direct result of contracting thramboxia. So, in addition to preventing thramboxia, the H1 vaccine prevents deaths.

Harjit responds to Jesse by

A. questioning the truth of a statement on which Jesse’s conclusion is based

B. suggesting that Jesse’s argument overlooks an important consequence

C. noting that Jesse’s argument contradicts that which he is trying to prove

D. reinforcing Jesse’s conclusion before suggesting a new conclusion

E. citing evidence that disproves the evidence cited by Jesse in drawing his conclusion


Practice Question

Jesse: The H1 vaccine prevents people from contracting thramboxia, a disease that can cause short-term paralysis. While thramboxia is an unpleasant disease with paralysis lasting up to 3 months, the H1 vaccine is not worth getting since hundreds of people die each year from the H1 vaccination.

Harjit: But thousands of people die each year as a direct result of contracting thramboxia. So, in addition to preventing thramboxia, the H1 vaccine prevents deaths.

Harjit responds to Jesse by

A. questioning the truth of a statement on which Jesse’s conclusion is based

B. suggesting that Jesse’s argument overlooks an important consequence

C. noting that Jesse’s argument contradicts that which he is trying to prove

D. reinforcing Jesse’s conclusion before suggesting a new conclusion

E. citing evidence that disproves the evidence cited by Jesse in drawing his conclusion

P: H1 prevents T

P: T can cause paralysis

P: 100s die from H1

C: Don’t get H1 vaccine

P: 1000’s die from T

P: H1 prevents T & deaths

C: Get H1 vaccine

There’s also Y. My option accomplishes 2 things




Practice Question

A. Very few people living in poorer communities are employed in the bakeries that make the bread.

B. In poorer communities, there are very few food alternatives to bread.

C. In poorer communities, bread is often the least expensive staple food, so when its price increases, people have less money to spend on other, more expensive foods.

D. Most people in poorer communities are unlikely to change their eating habits.

E. During some holidays, the consumption of food increases substantially.

For most products there exists an inverse relationship between price and consumption; if the price of a product increases, then consumption of that product decreases, and if the price decreases, consumption increases. However, in some poorer communities, when the price of bread increases, the consumption of bread increases.

Which of the following, if true, does the most to explain the paradoxical scenario?


Practice Question

P: $ then buying

P: Bread $ then buying

Paradox: People buy more bread when they should buy less

For most products there exists an inverse relationship between price and consumption; if the price of a product increases, then consumption of that product decreases, and if the price decreases, consumption increases. However, in some poorer communities, when the price of bread increases, the consumption of bread increases.

Which of the following, if true, does the most to explain the paradoxical scenario?

A. Very few people living in poorer communities are employed in the bakeries that make the bread.

B. In poorer communities, there are very few food alternatives to bread.

C. In poorer communities, bread is often the least expensive staple food, so when its price increases, people have less money to spend on other, more expensive foods.

D. Most people in poorer communities are unlikely to change their eating habits.

E. During some holidays, the consumption of food increases substantially.

Giffen good: A consumer good for which

consumption increases when price increases




Practice Question

It is very difficult for piano retailers to grow in the piano market. Despite population increases, the demand for pianos has remained constant for decades. Furthermore, when people decide to buy a piano, they typically go to the nearest piano retailer to make their purchase. Given this environment, a piano retailer can gain market share in the piano market only through purchasing its competitors, and not through aggressive marketing strategies.

Which of the following, if true, contributes most strongly to a refutation of the conclusion above?

A. Of the four mergers of piano retailers over the past six years, three led to a decline in profits for the newly-merged companies.

B. Through staff layoffs and warehouse closures, some of the larger piano retailers have achieved price reductions that are causing the smaller piano retailers to go out of business.

C. Most piano retailers sell a variety of products other than pianos.

D. Many public schools, traditionally responsible for almost half of all piano purchases, are eliminating their music programs in the face of severe budget cuts.

E. Several piano retailers have used aggressive marketing strategies such as publicity events, direct mail and in-store financing to increase customer loyalty.


Practice Question

It is very difficult for piano retailers to grow in the piano market. Despite population increases, the demand for pianos has remained constant for decades. Furthermore, when people decide to buy a piano, they typically go to the nearest piano retailer to make their purchase. Given this environment, a piano retailer can gain market share in the piano market only through purchasing its competitors, and not through aggressive marketing strategies.

Which of the following, if true, contributes most strongly to a refutation of the conclusion above?

A. Of the four mergers of piano retailers over the past six years, three led to a decline in profits for the newly-merged companies.

B. Through staff layoffs and warehouse closures, some of the larger piano retailers have achieved price reductions that are causing the smaller piano retailers to go out of business.

C. Most piano retailers sell a variety of products other than pianos.

D. Many public schools, traditionally responsible for almost half of all piano purchases, are eliminating their music programs in the face of severe budget cuts.

E. Several piano retailers have used aggressive marketing strategies such as publicity events, direct mail and in-store financing to increase customer loyalty.

P: Hard for retailer to grow

P: Demand constant

P: People buy from closest

C: share only through buying competitors

A: No other way to share




Practice Question

Maltania ranks far behind Finland and Sweden when it comes to employee job satisfaction. In all three countries, revenue-sharing programs and onsite daycare successfully increase job satisfaction. In Finland and Sweden, labor laws require companies with more than 10 employees to have revenue-sharing programs and onsite daycare. In Maltania, however, revenue-sharing programs and onsite daycare are found in only a few companies that have voluntarily established them.

Which of the following can be inferred from the statements above?

A. In Finland and Sweden, prior to the introduction of labor laws, the level of employee job satisfaction was similar to that in Maltania.

B. Revenue-sharing programs and onsite daycare are no more effective in increasing employee job satisfaction when they are established voluntarily than when they are established to comply with labor laws.

C. Establishing revenue-sharing programs and onsite daycare at all Maltanian companies with over 10 employees would increase employee job satisfaction in Maltania.

D. Companies with high job satisfaction typically have revenue-sharing programs.

E. Prior to the introduction of labor laws in Finland and Sweden, most companies with more than 10 employees did not have revenue-sharing programs and onsite daycare.


Practice Question

Maltania ranks far behind Finland and Sweden when it comes to employee job satisfaction. In all three countries, revenue-sharing programs and onsite daycare successfully increase job satisfaction. In Finland and Sweden, labor laws require companies with more than 10 employees to have revenue-sharing programs and onsite daycare. In Maltania, however, revenue-sharing programs and onsite daycare are found in only a few companies that have voluntarily established them.

Which of the following can be inferred from the statements above?

P: M behind F&S in JS

P: RS & DC JS

P: F&S must have RS & DC

P: M has voluntary RS & DC

A. In Finland and Sweden, prior to the introduction of labor laws, the level of employee job satisfaction was similar to that in Maltania.

B. Revenue-sharing programs and onsite daycare are no more effective in increasing employee job satisfaction when they are established voluntarily than when they are established to comply with labor laws.

C. Establishing revenue-sharing programs and onsite daycare at all Maltanian companies with over 10 employees would increase employee job satisfaction in Maltania.

D. Companies with high job satisfaction typically have revenue-sharing programs.

E. Prior to the introduction of labor laws in Finland and Sweden, most companies with more than 10 employees did not have revenue-sharing programs and onsite daycare.




Practice Question

Representative for the Maltanian Association of Cyclists: Over 1000 cyclists died in accidents last year. Accident reports indicate that 80% of the victims were not wearing a helmet at the time of their accident. This information indicates that, by wearing a helmet, cyclists can reduce their risk of dying if they are involved in an accident.

Which of the following, if true, best supports the representative’s argument?

A) The Maltanian Association of Cyclists is not funded by any helmet manufacturers.

B) Maltania has laws requiring all cyclists to wear a helmet.

C) Last year, less than 20% of the cyclists involved in accidents were not wearing a helmet at the time of the accident.

D) Most of the accidents in Maltania involve a cyclist and a motor vehicle.

E) Most of the cyclists who survived an accident last year indicate that their injuries would have been much worse had they not been wearing a helmet at the time.


Practice Question

Representative for the Maltanian Association of Cyclists: Over 1000 cyclists died in accidents last year. Accident reports indicate that 80% of the victims were not wearing a helmet at the time of their accident. This information indicates that, by wearing a helmet, cyclists can reduce their risk of dying if they are involved in an accident.

Which of the following, if true, best supports the representative’s argument?

P: 1000+ cyclist deaths

P: 80% of victims no helmet

C: Helmets save lives

A: Less than 80% of cyclists in accidents were not wearing a helmet

A) The Maltanian Association of Cyclists is not funded by any helmet manufacturers.

B) Maltania has laws requiring all cyclists to wear a helmet.

C) Last year, less than 20% of the cyclists involved in accidents were not wearing a helmet at the time of the accident.

D) Most of the accidents in Maltania involve a cyclist and a motor vehicle.

E) Most of the cyclists who survived an accident last year indicate that their injuries would have been much worse had they not been wearing a helmet at the time.




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