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 2×2 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, spanics and Asians? Suppose that Table 13.26 shows the results of a study. White Black spanic 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