chapter 1

78. Let µ1denote the true average ratio for young men and µ2denote the true average ratio forelderly men. Assuming both populations from which these samples were taken are normallydistributed, the relevant hypotheses are H µ − µ 0 vs. H µ − µ 0 . Thevalue of the test statistic ist =( 7.47 − 6.71)2(.22) (.28)0:1 2=2= 7.5a:1 2>. The d.f. = 20 and the p-value is+13 12≈ . Since the p-value is < α = . 05 , we reject H o . We have sufficient evidenceP( t > 7.5) 0to claim that the true average ratio for young men exceeds that for elderly men.79.42.5Poor Visibility32Good Visibility1.50.51-10Normal Score1-10Normal Score1A normal probability plot indicates the data for good visibility does not follow a normaldistribution, thus a t-test is not appropriate for this small a sample size.µM= µ versusMµFµ ≠ for both the distress and80. The relevant hypotheses would beFdelight indices. The reported p-value for the test of mean differences on the distress indexwas less than 0.001. This indicates a statistically significant difference in the mean scores,with the mean score for women being higher. The reported p-value for the test of meandifferences on the delight index was > 0.05. This indicates a lack of statistical significance inthe difference of delight index scores for men and women.261