Lane: Chapter 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 – Years olds 16- Years olds
66 74
68 71
59 67
30 Minutes 72 82
46 76
69 95
61 92
69 95
60 Minutes73 98
61 94
ADHD Treatment (AT) case study
28. (AT) The dataset ADHD Treatment has four scores per subject. a. Is the designbetween-subjects or within-subjects? b. Create an ANOVA summary table.
29. (AT) Using the Anger Expression Index from the Angry Moods study as the dependent variable, perform a 2×2 ANOVA with gender and sportsparticipation as the two factors. Do athletes and non-athletes differ significantly in how much anger they express? Do the genders differ significantly in AngerExpression Index? Is the effect of sports participation significantly different forthe two genders?
Illowsky: Chapter 13.
13.2 The F Distribution and the F-Ratio
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 followingdata 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 ¯= ________ ________ ________ ________________
s2 =________ ________ ________ ________ ________
H0: μ1 = μ2 = μ3 = μ4 = μ5
Hα: At least any two of the group means μ1, μ2, …, μ5 are not equal.
61. degrees of freedom – numerator: df(num) = _________
62. degrees of freedom – denominator: df(denom) = ________
63. F statistic = ________
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
Table 13.24
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
Table 13.26
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.
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.
Table 13.32
Working-classprofessional (middle incomes) professional (wealthy)
17.8 16.5 8.5
26.7 17.4 6.3
49.4 22.0 4.6
9.47.4 12.6
65.4 9.4 11.0
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
15061 124 39
94 19 50 127
62 99 31 141
73 60 11873
89