2. The college bookstore tells prospective students that the average cost of its textbooks is $32 per book with a standard deviation of $4.50. The engineering students think that the average cost is higher. To test the claim made by the bookstore, a sample of 45 books is considered and ) x = 1470.25 . Perform an appropriate test at 5% level of significance. 3. A comparative study was made between two subspecies of dark-eyed juncos. The wing lengths of 14 members of each subspecies were measured and the following is the summary statistics: x1 = 82.1, X2 = 84.9, $1 = 1.501, S2 = 1.698, n1 = 14, n2 = 14 Construct a 95% confidence interval for the difference of two mean wing lengths. (Assume the two population standard deviations to be unequal)