The annual NFL Super Bowl is the most widely watched sporting event in the United States each year. In recent years, there has been a great deal of interest in the ads that appear during the game. These ads vary in length with most lasting 30 seconds or 60 seconds. The file SuperBowlAdScore contains the ad length and ad scores from a recent Super Bowl.

Source: Data extracted from C. Woodyard, “Funny Bone Wins Out,” USA Today, February 6, 2016, p. 4B.

a. Is there evidence of a difference in the variability of the scores between the two types of ads? (Use α = 0.05.)

b. Determine the p-value in (a) and interpret its meaning.

c. What assumption about the population distribution of the two types of ads is necessary in (a)? Is the assumption valid for these data?

d. Based on the results of (a), which t test defined in Section 10.1 should you use to compare the mean scores of the two types of ads?