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 SuperBowl.

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

For the 30-second ads and the 60-second ads separately:

a. Construct a 95% confidence interval estimate for the population mean ad score.

b. Interpret the interval constructed in (a).

c. What conclusions can you reach about the ad scores of 30-second and 60-second ads?

d. What assumption must you make about the population distribution in order to construct the confidence interval estimate in (a)?

e. Do you think that the assumption needed in order to construct the confidence interval estimate in (a) is valid? Explain.