Automobile insurance companies take many factors into consideration when setting rates. These factors include age, marital status, and miles driven per year. To determine the effect of gender, a random sample of young (under 25, with at least 2 years of driving experience) male and female drivers was surveyed. Each was asked how many miles he or she had driven in the past year. The distances (in thousands of miles) are stored in stacked format (column 1 = driving distances and column 2 identifies the gender where 1 = male and code 2 = female).

a. Can we conclude that male and female drivers differ in the numbers of miles driven per year?

b. Estimate with 95% confidence the difference in mean distance driven by male and female drivers.

c. Check to ensure that the required condition(s) of the techniques used in parts (a) and (b) is satisfied.