17. The director of human resources for a large bank has compiled data on about 70 former employees at one of the bank’s call centers (see the Excel file Call Center Data). For each of the following, assume equal variances of the two populations.

a. Test the null hypothesis that the average length of service for males is the same as for females.

b. Test the null hypothesis that the average length of service for individuals without prior call center experience is the same as those with experience.

c. Test the null hypothesis that the average length of service for individuals with a college degree is the same as for individuals without a college degree.

d. Now conduct tests of hypotheses for equality of variances. Were your assumptions of equal variances valid? If not, repeat the test(s) for means using the unequal variance test.