Do men and women differ in the number of online friends that they have? A study of 3,011 people reported that men had a mean of 180 friends and women had a mean of 140 friends. Suppose that the study consisted of 1,511 men and 1,500 women and that the standard deviation of the number of friends was 130 for men and 120 for women. Assume a level of significance of 0.05.
a. Is there evidence of a difference in the variances of the number of online friends between men and women?
b. Is there evidence of a difference in the mean number of online friends between men and women?
c. Construct and interpret a 95% confidence interval estimate for the difference in the mean number of online friends between men and women.