Stress and Headaches In the study, researchers found that the
greater the stress in a person's life, the more intense and
frequent their headaches were.
Slide 4
Correlation A = amount of stress B = strength and number of
headaches A is positively correlated with B B is positively
correlated with A
Slide 5
Explanation for Correlation Possible causal structures: A
causes B B causes A Some other variable C causes both A and B.
Slide 6
Researchers Explanation for Correlation Possible causal
structures: A causes B B causes A Some other variable C causes both
A and B.
Slide 7
Explanation for Explanation Stress causes headaches. Why?
Slide 8
The Article Does Not Say! Although headaches can be triggered
by many factors, ranging from muscle strain to exposure to noxious
gases, stress clearly plays a major role. Clearly? Why?
Slide 9
Posit a Mechanism Stress causes an increase in the hormone
adrenaline. Adrenaline opens blood vessels for faster flowing
blood, and quicker reaction. Elevated levels of adrenaline over
long times can cause the blood vessels in the head to send
pain-signals to the brain. Thats why Stress causes headaches.
Slide 10
Facebook and Body Image Problems Female students who spend a
lot of time on the social networking site tend to be more body
conscious and to suffer from more anxiety.
Slide 11
Facebook and Body Image Problems They also tend to give greater
significance to the number of comments and likes on their pictures
and status updates. They are more likely to untag themselves in
pictures.
Slide 12
Correlation A = time that young women spent looking at pictures
on facebook B = unhealthy body image A is positively correlated
with B B is positively correlated with A
Slide 13
One Explanation A B Looking at pictures longer on facebook
causes an unhealthy body image in young women.
Slide 14
Mechanism A X B Looking at pictures longer on facebook causes
women to compare themselves with others and this causes an
unhealthy body image.
Slide 15
NOT a Different Explanation A X B Providing a mechanism is not
the same thing as providing a different explanation for the
correlation. This is still the A B explanation.
Slide 16
Tracing Causes Back X A B Having easier access to computers
causes looking at pictures longer on facebook, which then causes an
unhealthy body image in young women.
Slide 17
NOT a Different Explanation X A B Tracing the causes back
further is not the same thing as providing a different explanation.
Here we are still assuming that A causes B, we are just explaining
what causes A.
Slide 18
Widening the Target A B Facebook and twitter and instagram and
tublr and all cause looking at pictures longer on, which then
causes an unhealthy body image in young women. X
Slide 19
Also NOT a Different Explanation A B Again, this explanation
still says that A causes B, it just lists a bunch of other causes
of B. X
Slide 20
Sex and Money [P]eople who had more money, reported more sexual
satisfaction.
Slide 21
Sex and Money [P]eople who had more money, reported more sexual
satisfaction.
Slide 22
Sex and Money A = socioeconomic status ($$$) B = sexual
satisfaction A is positively correlated with B B is positively
correlated with A
Slide 23
Tracing Back the Causes X A B Being educated causes one to
acquire wealth. Wealth attracts better sexual partners.
Slide 24
True Common Cause A C B Being educated causes one to acquire
wealth. Being educated also causes one to have a better awareness
of ones need and thus to have better sex.
Slide 25
Doesnt Always Make Sense A C B Living in a prosperous country
causes one to acquire wealth. Living in a prosperous country also
causes one to have a better awareness of ones need and thus to have
better sex.
Slide 26
Doesnt Always Make Sense A C B Everyone in the study was from
Spain!
Slide 27
Midterm Exam
Slide 28
Problem #1 After the nuclear disaster at Fukushima, lots of
people rushed out to buy iodized salt. These people thought that
three men make a tiger and if enough people say something is true,
then it is. This is just the appeal to popularity, and it is a bad
way to form your ideas.
Slide 29
Problem #1 That is why I know that iodized salt does not
protect from nuclear radiation. Based on the information we learned
in class, what is the main flaw with this argument?
Slide 30
The Fallacy Fallacy This is a bad argument: 1.You have
presented argument A for your claim C. 2.A is a fallacious
argument. 3.Therefore, C is false.
Slide 31
Problem #2 Imagine that a school decides to try a new way to
teach reading to its students. They use the new teaching method
over an entire term and discover that 80% of the students test
better in reading proficiency at the end of the term, compared with
how they tested at the beginning. The school concludes that the new
way of teaching reading works, and they decide to keep using it in
the future. Based on the information that we learned in class, what
is the main problem with the conclusion the school reaches? What
should they have done instead?
Slide 32
Slide 33
Theres No Control Group Of course students will get better at
reading after an entire year of teaching. What we want to know is
whether the new method works better than the old method. So we need
two group: the experimental group using the new method and a
control group using the old method.
Slide 34
Problem #3 Neglecting to follow a dentists directives can lead
to heart disease, high blood pressure, and stroke and thats only a
glimpse of the possible adverse effects of ignoring the importance
of good oral health.
Slide 35
Problem #3 The scary part is that 40 percent of people with
heart conditions have gum disease, Dr. Kabour said. The big
question they ask is how it happens: Bacteria that grows on the
gums affects the inner layer of the heart, which builds up plaque
over the years.
Slide 36
Problem #3 According to this story, which two variables are
correlated? What is the researchers explanation for the
correlation? Please offer an explanation of the correlation that
differs from the one provided by the researcher.
Slide 37
Correlation A = gum disease B = heart disease A is positively
correlated with B B is positively correlated with A
Slide 38
Researchers Explanation Theres a common cause: gum disease is
caused by bacteria that grows on the gums. This bacteria also
affects the heart, and causes it to build up plaque over many
years.
Slide 39
Correlation A = doing what the dentist says B = heart disease A
is negatively correlated with B B is negatively correlated with
A
Slide 40
Researchers Explanation A causes B. Not doing what the dentist
says causes bacteria to grow on your gums. This bacteria then
affects the heart, and causes it to build up plaque over many
years.
Slide 41
Alternate Explanation Theres a common cause: sugar. Consuming
sugar causes bacteria to grow on your gums and then causes gum
disease. But tooth-decay is NOT what causes heart problems. The
sugar does. Sugar causes weight gain and this strains your
heart.
Slide 42
Researchers Explanation You can tell this is a different
explanation because what it recommends is different. Good oral
hygiene will not prevent heart disease, if this explanation is
true: only removing sugar from your diet will.
Slide 43
Problem #4 Using figures from the last election, researchers
discover that districts in Hong Kong that were wealthier (higher
average income) were also districts that voted more for
pro-democratic politicians from the Civic, Democratic, and People
Power parties. Districts that were poorer voted more for
pro-Beijing politicains from DAB, FTU, and NPP. Using the
information that we learned in class, explain why these results
should not lead us to believe that wealthier people are more likely
to be pro-democratic.
Slide 44
Blue = Democrat
Slide 45
Green = $$$
Slide 46
Ecological Fallacy States with the highest average incomes have
a higher percentage of democratic voters. So does this mean that
people who are wealthy are more likely to vote democrat? No! The
opposite is true.
Slide 47
Nanotips Gloves that work with touchscreens arent new, but
theyre usually sold at a premium and have to be bought separately
from your existing gloves.
Slide 48
Nanotips A new technology claims to solve this problem by
letting you turn any pair of ordinary into touchscreen ones simply
by painting the fingertips with a special liquid. Called Nanotips,
the liquid is made of conductive polyamide that soaks into the
fabric and builds a conductive 'bridge' between your finger and the
screen.
Slide 49
Nanotips A Nanotips pack costs $20 (12) but can be used on
multiple gloves. Shipping costs $3.50 and it is due to go on sale
on 20 March. The company does ship internationally.
Slide 50
Its an advertisement disguised as news!
http://www.dailymail.co.uk/sciencetech/article-2580983/Now-ANY-
gloves-work-touchscreen-12-paint-transforms-woolly-fingertips-
prosthetic-limbs.html
Slide 51
Hints Detailed description of the product No discussion of
alternatives Pricing information Information about international
shipping How is any of that news?
Slide 52
Ah Shi Point Acupuncture Ah shi point acupuncture involves
inserting needles at painful places on the body, unlike regular
acupuncture.
Slide 53
Problem #6 http://www.ncbi.nlm.nih.gov/pubmed/20813813 Here is
a description of a scientific experiment on ah shi point
acupuncture as a treatment for acne: 36 subjects were randomized in
a double-blind controlled trial. The control group received
acupuncture at general acupuncture points only, and the
experimental group received acupuncture at both general acupuncture
points and ah shi points.
Slide 54
Slide 55
Problem #6 The study involved 12 acupuncture sessions over six
weeks. It found there was a significant reduction in the amount of
acne in both groups, but the experimental group did not do better
or worse than the control group. The researchers concluded that
acupuncture was an effective treatment for acne. Based on the
information that we learned in class, what is the main reason this
scientific study does not support the researchers conclusion?
Slide 56
No Controls, Again There was no no-acupuncture/ fake
acupuncture control group. This study shows that ah shi point
acupuncture does not work better than regular acupuncture. It does
not show that acupuncture works better than no-acupuncture, because
there was no no-acupuncture/ fake acupuncture control group. Maybe
all three groups would have improved equally.
Slide 57
Problem #7 The Malaysian prime minister once made the following
argument: It is bad to give successful Malaysian badminton players
lots of money and fame when they achieve great international
success. Every player that has achieved great international
success, and then been given lots of money and fame, has gone on to
play worse in their next tournament. Based on the information that
we learned in class, what is the main flaw in the prime ministers
argument?
Slide 58
Regression to the Mean Whenever two variables are imperfectly
correlated, extreme values of one variable tend to be paired with
less extreme values of the other.
Slide 59
Regression Fallacy The regression fallacy is when you attribute
a cause to a regression effect. Jeremy Lin lost after appearing on
Sports Illustrated. A curse!
Slide 60
The Sports Illustrated Jinx For example, while this was the
cover of SI in February, Jeremy Lin shot 1-for-11 in a game where
the New York Knicks lost to the Miami Heat 102-88.
Slide 61
Malaysian Badminton Players When do badminton players receive
fame and money? When they are doing unusually well. Subsequently
they regress to the mean and do less well. Its not because they got
fame and money, its because whenever two variables are imperfectly
correlated, extreme values of one variable tend to be paired with
less extreme values of the other.
Slide 62
Problem #8 It is natural for women to have children. All female
animals are designed to reproduce their species. The only reason
any of us exists is because our mothers birthed us into this
world.
Slide 63
Problem #8 Therefore it is wrong for women to choose to have
careers instead of having children, and it is wrong that our
society so often forces women to work instead of staying home and
having children.
Slide 64
Problem #8 Based on the information we learned in class, what
is the main flaw in this argument?
Slide 65
Appeal to Nature The appeal to nature fallacy is when someone
argues that something is true/ good because its natural or when
they argue that something is false/ bad because its unnatural.
Slide 66
Problem #9 Grand Theft Auto V is one of the best-selling video
games of all time. It was available on two video game consoles:
Sonys Playstation 3 (PS3) and Microsofts Xbox 360. More people
purchased the game for PS3 than for Xbox 360.
Slide 67
Problem #9 Based on the information we learned in class,
explain why the following chart is misleading.
Slide 68
Some Things to Note Its a truncated chart. The Y-axis does not
start at zero. The chart exaggerates the difference in preference
between the PS3 and the Xbox 360. The real difference is 3%. The
portrayed difference is 200%.
Slide 69
Video Time!
http://www.economist.com/multimedia?bclid=1294626183001&bctid
=2719450974001
Slide 70
Problem #10 Science tests hypotheses about the causal structure
of the world. Only about 1 in 10 hypotheses are true. This is
because, for example, there are more things that do not cause
cancer than things that do cause cancer. So most hypotheses about
the causes of cancer will be false.
Slide 71
Only 1 in 10 hypotheses are true.
Slide 72
Problem #10 Suppose I conduct an experiment to test the
hypothesis that A causes B. The results of the experiment seem to
confirm the hypothesis. I know that if A does cause B, then I would
get these results 95% of the time
Slide 73
95% of true hypotheses test positive.
Slide 74
Thats these ones.
Slide 75
Problem #10 and if A does not cause B, I would get these
results only 5% of the time.
Slide 76
5% of false hypotheses test positive.
Slide 77
Thats these ones.
Slide 78
Problem #10 Given the information that we learned in class, how
certain should I be that A causes B? Please explain your
answer.
Slide 79
High proportion of false positives.
Slide 80
Answer Theres only about a 64% chance that the correlation I
found is due to true hypothesis.
Slide 81
Base Rate Neglect Fallacy The base rate neglect fallacy happens
when: 1.There is a low base rate of some condition. 2.We have a
test for that condition. 3.Someone tests positive. 4.We assume that
means they have the condition, ignoring the unreliability of tests
for conditions with low base rates.
Slide 82
Importance of Base Rates As the base rate decreases, the
proportion of false positives out of total positives increases:
False Positive False Positive + True Positive
