Answer Happy

A paper describes an investigation in which 40 men and 40 women with online dating profiles agreed to participate in a study. Each participant's height (in inches) was measured and the actual height was compared to the height given in that person's online profile. The differences between the online profile height and the actual height (profile - actual) were used to compute the values in the accompanying table. Men Women * = 0.56 S = 0.81 * = 0.09 S = 0.75 n = 40 n = 40 For purposes of this exercise, assume it is reasonable to regard the two samples in this study as being representative of male online daters and female online daters. (Although the authors of the paper believed that their samples were representative of these populations, participants were volunteers recruited through newspaper advertisements, so we should be a bit hesitant to generalize results to all online daters.)

Use the two-sample t test of Section 11.1 to test Ho: 4m-up = 0 versus H: 4m - Mp>0, where xm is the mean height difference (profile - actual) for male online daters and My is the mean height difference (profile - actual) for female online daters. (Use a = 0.05. Use a statistical computer package to calculate the P-value. Round your test statistic to two decimal places, your df down to the nearest whole number, and your P-value to three decimal places.) t = 2.69 df = 78 P-value = 0.004