In Exercise 5.8

(p. 266) we examined research about bicycle helmets reported in Public Health Reports

(May-June 1992). One of the variables measured was the children's perception of the risk involved in bicycling. A random sample of 797 children in grades 4-6 were asked to rate their perception of bicycle risk without wearing a helmet, ranging from 1 (no risk) to 4

(very high risk). The mean and standard deviation of the sample were i = 3.39, s = 80, respectively.

a. Assume that a mean score, p, of 2.5 is indicative of indifference to risk, and values of p exceeding 2.5 indicate a perception that a risk exists. What are the appropriate null and alternative hypotheses for tcsting the research hypothesis that children in this age group perceive a risk associated with failure to wear helmets?

b. Calculate the p-value for the data collected in this study.

c. Interpret the p-value in the context of this research.

638 Refer to Exercise 6.22

(p. 311), in which a random sample of 49 unemployed men were administered the General Health Questionnaire (GHQ). The sample mean and standard deviation wcrc 10.94 and 5.10, respectively. Denoting the population mean GHQ for unemployed workers by p, we wish to test the null hypothesis H,: p = 10 versus the one-tailed alternative Ha: p > 10.

a. When the data are run through MINITAB, the results (in part) are as shown in the printout below.
Check the program's results for accuracy.

b. What conclusion would you reach about the test based on the computer analysis?