Homework

Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Slide 9- 1

Homework

Homework Assignment #34 Review Section 9.8 Page 782, Exercises: 1 – 45(EOO), 47


Homework, Page 782

1. Identify whether the number described is a parameter or a statistic.

a. The average score on last week’s quiz was 73.4.

Parameter

b. About 13% of the population is left-handed.

Statistic

c. In a study of laboratory rats, 93% became aggressive when deprived of sleep.

Statistic


Homework, Page 782Find the mean of the data set.

5. {32.4, 48.1, 85.3, 67.2, 72.4, 55.3}

32.4 48.1 85.3 67.2 72.4 55.360.117

6


Homework, Page 782Find the mean of the indicated data.

9. The number of moons.Planet Moons

Mercury 0

Venus 0

Earth 1

Mars 2

Jupiter 61

Saturn 33

Uranus 26

Neptune 13

Pluto 1

0 0 1 2 61 33 26 13 115.2

9


Homework, Page 78213. Determine the average annual home run production for Willie Mays and for Mickey Mantle for their career totals of 660 over 22 years and 536 over 18 years, respectively. Who had the greater production rate?

660Mays : 30.0

22536

Mantle : 29.7818

Willie Mays had the better production rate.


Homework, Page 78217. Find the median and mode of the numbers in the table.

Mean = 84.823

There is no mode, as five numbers appear two times each and none appear more than two times.

79.5 87.5 88.5 89.2 91.6 84.5

82.1 82.3 85.7 89.8 84.0 84.8

88.2 88.2 82.9 89.8 89.2 94.1

88.0 91.1 91.8 87.0 87.7 88.0

85.4 94.4 91.3 86.4 85.7 86.0


Homework, Page 78221. Use the data in the table to find:

A) The average (mean) monthly low temperatures for Beijing.

B) Find the weighted average using the days in the month and assuming no leap year.

C) Compare the results above. Do the weights have an effect? Why or why not? Which average is a better indicator?

The weights only have a slight effect because the numbers of days per month vary slightly. The weighted average is better.

31 9 28 7 31 1 30 7 3113 30 18

31 22 31 21 30 14 31 7 30 1 31 7Avg. Monthly Low

365 6.49 C

9 7 1 7 13 18 22 21 14 7 1 7Avg. Monthly Low

12 6.42 C


Homework, Page 782Determine the five-number summary, the range, and the inter-quartile range for given data. Identify any outliers.

25. The following salaries for the employees in one department of the Garcia Brothers Co. (in thousands of dollars): 33.5, 35.3, 33.8, 29.3, 36.7, 32.8, 31.7, 37.3, 33.5, 28.2, 34.8, 33.5, 29.7, 38.5, 32.7, 34.8, 34.2, 31.6, 35.4

To find the five-number summary, first arrange the numbers in

ascending order: 28.2, 29.3, 29.7, 31.6, 31.7, 32.7, 32.8, 33.5,

33.5, 33.5, 33.8, 34.2, 34.8, 34.8, 35.3, 35.4, 36.7, 37.3, 38.5

The minimu

m is 28.2, the median is 33.5, the first quartile is

31.7, the third quartile is 35.3, and the maximum is 38.5. The

five number summary is: 28.2,31.7,33.5,35.3,38.5 ; the range

is 10.3, the interquartile range is 3.6, and there are no outliers.


Homework, Page 782Refer to the wind speed data in exercise 24.

29. Some wind turbine generators, to be efficient generators of power, require average wind speeds of at least 10.5 mph. Approximately what fraction of the climatic centers are suited for these wind turbine generators?

Of the 44 centers, 12 or 3/11 of the climatic centers are suited for these wind turbine generators.


Homework, Page 782Find the standard deviation and variance of the data set.

33. {23, 45, 29, 34, 39, 41, 19, 22}

2

standard deviation, 9.0829

variance, 82.50


Homework, Page 782Find the standard deviation and variance of the data set.

37. The data in exercise 24.

2

standard deviation, 11.9597

variance, 143.035


Homework, Page 78241. In 1995, scores on the Scholastic Aptitude Test were re-scaled to their original mean of 500 with an approximate standard deviation of 100. SAT scores in the general population have a normal distribution. A) Approximately what percentage of 1995 scores fell between 400 and 600.Approximately 68% percent of the scores fell between 400 and 600.

B) Approximately what percentage of 1995 scores fell below 300?Approximately 2.5% percent of the scores fell below 300.

C) By 2001, the national average on the SAT Math section was 514. Is this number a parameter or statistic?The number 514 is a parameter, since it applies to the entire population.


Homework, Page 782

45. The plot of a normal distribution will be

A) symmetric

B) skewed left

C) skewed right

D) lower in the middle than at the ends

E) of no predictable shape


Homework, Page 78247. Professor Mitchell grades the exams of his 30 students and finds the scores have a mean of 81.3 and a median of 80.5. He later determines that the top student deserves 9 extra points for a misgraded proof. After the error is corrected, the scores have

A) a mean of 81.3 and a median of 80.5

B) a mean of 81.6 and a median of 80.5

C) a mean of 81.6 and a median of 80.8

D) a mean of 90.3 and a median of 80.5

E) a mean of 90.3 and a median of 89.5

81.3 30 981.6, median is unchanged as only

30the top grade increased.


Homework

Homework Assignment #35 Review Sections 9.1 – 9.8 Page 786, Exercises: 1 – 113 (EOO) Chapter 9 test next time

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