51. Consider a sample with n = 25 and x-bar = 45. The population standard deviation is known to be 15. a ) Construct the 95% confidence interval for the mean. b) Using the results of part (a) determine the margin error. 5ii. Assume that the following values represent random observations from a normal parent population of daily computer builds conducted by IT field support team: 3 4 5 2 9 0 8 4 C) Construct the 99% confidence interval for the mean. d) What is the (1-a)% CI that will decrease the margin of error calculated in part a) by half using the same sample standard deviation