The following data represent weights (in pounds) for two random samples of men of approximately 5 feet 10 inches tall and of medium build. The only difference is that the first group is comprised of athletic persons and the second of non-athletic ones. Weights are assumed to follow normal distributions. Athletic men: 152, 148, 156, 155, 157, 162, 159, 168, 150, 173. Non-athletic men: 155, 157, 169, 170, 171, 161, 181, 165, 183.

C) At the 5% level of significance, can we infer that the population mean weight of athletic men is lower than the population mean weight of non-athletic men by more than 2 pounds?

D) Estimate with 90% confidence the difference in the mean weight between the two groups.

E) After having compared the means of the weights of the two groups, can we conclude at the 5% significance level that the variance of the weights of the non-athletic men is larger that the variance of the weights of the athletic men?