Tobacco and Alcohol Use in Animated Children’s Movies Data Set 7 in Appendix B lists times (in seconds) that animated children’s movies show tobacco use and alcohol use. The 50 times of tobacco use have a mean of 57.4 sec and a standard deviation of 104.0 sec. The 50 times of alcohol use have a mean of 32.46 sec and a standard deviation of 66.3 sec.

a. Assuming that we want to use the methods of this section to test the claim that the times of tobacco use and the times of alcohol use have different standard deviations, identify the F test statistic, critical value, and conclusion. Use a 0.05 significance level.

b. Consider the prerequisite of normally distributed populations. Instead of constructing histograms or normal quantile plots, simply examine the numbers of movies showing no tobacco or alcohol use. Are the times for tobacco use normally distributed? Are the times for alcohol use normally distributed?

c. What can be concluded from the results of parts

(a) and (b)?