# Project #31014 - Statistics

"t-test" in the Calculations section of the "Statistics Visual Learner" media piece.

Complete the following exercises from "Questions and Problems" located at the end of each chapter and put them into a Word document to be submitted as directed by the instructor.

1. Chapter Thirteen # 3, 12, 14, 20

2. Chapter Fourteen # 14, 17, 23

CHAPTER 13

(3). Elaborate on what is meant by degrees of freedom.

Use an example.

(12). A sample set of 29 scores has a mean of 76 and a

standard deviation of 7. Can we accept the hypothesis

that the sample is a random sample from a population

with a mean greater than 72? Use _ _ 0.011 tail in

(14). Using each of the following random samples, determine

the 95% and 99% confidence intervals for the

population mean:

a. Xobt _ 25, s _ 6, N _ 15

b. Xobt _ 120, s _ 8, N _ 30

c. Xobt _ 30.6, s _ 5.5, N _ 24

d. Redo part a with N _ 30. What happens to the

confidence interval as N increases? Other

(20). A physician employed by a large corporation believes

that due to an increase in sedentary life in the past

decade, middle-age men have become fatter. In 1995,

the corporation measured the percentage of fat in

their employees. For the middle-age men, the scores

were normally distributed, with a mean of 22%. To

test her hypothesis, the physician measures the fat

percentage in a random sample of 12 middle-age

men currently employed by the corporation. The fat

percentages found were as follows: 24, 40, 29, 32, 33,

25, 15, 22, 18, 25, 16, 27. On the basis of these data,

can we conclude that middle-age men employed by

the corporation have become fatter? Assume a directional

H1 is legitimate and use _ _ 0.051 tail in making your decision. Health

CHAPTER 14

(14). You are interested in determining whether an

experimental birth control pill has the side effect

of changing blood pressure. You randomly sample

ten women from the city in which you live. You

give five of them a placebo for a month and then

measure their diastolic blood pressure. Then you

switch them to the birth control pill for a month

and again measure their blood pressure. The other five women receive the same treatment except they

are given the birth control pill first for a month,

followed by the placebo for a month. The blood

pressure readings are shown here. Note that to

safeguard the women from unwanted pregnancy,

another means of birth control that does not interact

with the pill was used for the duration of the

experiment.

Diastolic Blood Pressure

Subject No.

Birth control

pill Placebo

1 108 102

2 76 68

3 69 66

4 78 71

5 74 76

6 85 80

7 79 82

8 78 79

9 80 78

10 81 85

a. What is the alternative hypothesis? Assume a

nondirectional hypothesis is appropriate.

b. What is the null hypothesis?

c. What do you conclude? Use _ _ 0.012 tail. social,

biological, health

(17). The manager of the cosmetics section of a large

department store wants to determine whether

newspaper advertising really does affect sales. For

her experiment, she randomly selects 15 items currently

in stock and proceeds to establish a baseline.

The 15 items are priced at their usual competitive

values, and the quantity of each item sold for a

1-week period is recorded. Then, without changing

their price, she places a large ad in the newspaper,

advertising the 15 items. Again, she records

the quantity sold for a 1-week period. The results

follow.

Item

No. Sold

No. Sold

1 25 32

2 18 24

3 3 7

4 42 40

5 16 19

6 20 25

7 23 23

8 32 35

9 60 65

10 40 43

11 27 28

12 7 11

13 13 12

14 23 32

15 16 28

a. Using _ _ 0.052 tail, what do you conclude?

b. What is the size of the effect? I/O

(23). An educator wants to determine whether early exposure

to school will affect IQ. He enlists the aid of the

parents of 12 pairs of preschool-age identical twins

who agree to let their twins participate in this experiment.

One member of each twin pair is enrolled in

preschool for 2 years while the other member of each

pair remains at home. At the end of the 2 years, the IQs

of all the children are measured. The results follow.

IQ

Pair

Twin at

preschool

Twin at

home

1 110 114

2 121 118

3 107 103

4 117 112

5 115 117

6 112 106

7 130 125

8 116 113

9 111 109

10 120 122

11 117 116

12 106 104

Does early exposure to school affect IQ? Use

_ _ 0.052 tail.

cognitive, developmental, education

 Subject Mathematics Due By (Pacific Time) 05/18/2014 12:00 am
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