STAT200 WEEK 8 HOMEWORK A+++++

Lane – Ch. 15

10. If an experiment is conducted with 5 conditions and 6 subjects in each condition, what are dfn and dfe?

17. The following data are from a hypothetical study on the effects of age and time on scores on a test of reading comprehension. Compute the analysis of variance summary table.

12-year-olds

16-year-olds

30 minutes

66

74

68

71

59

67

72

82

46

76

60 minutes

69

95

61

92

69

95

73

98

61

94

Illowsky – Ch. 13

Use the following information to answer the next three exercises. Suppose a group is interested in determining whether teenagers obtain their drivers licenses at approximately the same average age across the country. Suppose that the following data are randomly collected from five teenagers in each region of the country. The numbers represent the age at which teenagers obtained their drivers licenses.

Northeast

South

West

Central

East

16.3

16.9

16.4

16.2

17.1

16.1

16.5

16.5

16.6

17.2

16.4

16.4

16.6

16.5

16.6

16.5

16.2

16.1

16.4

16.8

x-bar =

________

________

________

________

________

s^2 =

________

________

________

________

________

H0:µ1=µ2=µ3=µ4=µ5

Hα: At least any two of the group meansµ1,µ2, …,µ5are not equal.

61. degrees of freedom – numerator: df(num) = ________

63. F static = ________

69. A researcher wants to know if the mean times (in minutes) that people watch their favorite news station are the same. Suppose that Table 13.24 shows the results of a study.

CNN FOX Local

45 15 72

12 43 37

18 68 56

38 50 60

23 31 51

35 22 ?

Assume that all distributions are normal, the four population standard deviations are approximately the same, and the data were collected independently and randomly. Use a level of significance of 0.05.

71. Are the mean number of times a month a person eats out the same for whites, blacks, Hispanics and Asians? Suppose that Table 13.26 shows the results of a study.

White

Black

Hispanic

Asian

6

4

7

8

8

1

3

3

2

5

5

5

4

2

4

1

6

6

7

77. A grassroots group opposed to a proposed increase in the gas tax claimed that the increase would hurt working-class people the most, since they commute the farthest to work. Suppose that the group randomly surveyed 24 individuals and asked them their daily one-way commuting mileage. The results are as follows.

Working-Class

Professional (middles incomes)

Professional (wealthy)

17.8

16.5

8.5

26.7

17.4

6.3

49.4

22

4.6

9.4

7.4

12.6

65.4

9.4

11

47.1

2.1

28.6

19.5

6.4

15.4

51.2

13.9

9.3

Determine whether or not the variance in mileage driven is statistically the same among the working class and professional (middle income) groups. Use a 5% significance level.

81. Is the variance for the amount of money, in dollars, that shoppers spend on Saturdays at the mall the same as the variance for the amount of money that shoppers spend on Sundays at the mall? Suppose that the Table 13.34 shows the results of a study.

Saturday

Sunday

Saturday

Sunday

75

44

62

137

18

58

0

82

150

61

124

39

94

19

50

127

62

99

31

141

73

60

118

73

89

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