An important feature of tablets is battery life, the number of hours before the battery needs to be recharged. The file Tablets contains the battery life of 12 WiFi-only and 7 3G/4G/WiFi 9- through...

An important feature of tablets is battery life, the number of hours before the battery needs to be recharged. The file Tablets contains the battery life of 12 WiFi-only and 7 3G/4G/WiFi 9- through 12-inch tablets. (Data extracted from “Ratings and recommendations: Tablets,” Consumer Reports, August 2013, p. 46.)

a. Is there evidence of a difference in the variability of the battery life between the two types of tablets? (Use a = 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 tablets 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 battery life of the two types of tablets?