Question

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
68
59
72
46    74
71
67
82
76


60 minutes

    69
61
69
73
61    95
92
95
98
94

28. ADHD Treatment (AT) case study:
(AT) The dataset ADHD Treatment has four scores per subject.
a. Is the design between-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 2x2 ANOVA with gender and sports participation as the two factors. Do athletes and non-athletes differ significantly in how much anger they express? Do the genders differ significantly in Anger Expression Index? Is the effect of sports participation significantly different for the two genders?

The F Distribution and the F-Ratio
Use the following information to answer the next TWO exercises (61 & 63). 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 ¯=                   
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) = _________
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:
Working-class    Professional (middle incomes)    Professional (wealthy)
17.8    16.5    8.5
26.7    17.4    6.3
49.4    22.0    4.6
9.4    7.4    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
150    61    124    39
94    19    50    127
62    99    31    141
73    60    118    73
89           
Table 13.34