In a random sample of 15 computers, the mean repair cost was $100 and the standard deviation was $42.50. Assume that the repair cost of computers follows a normal distribution. Construct a 95%...

 In a random sample of 15 computers, the mean repair cost was $100 and the standard deviation was $42.50. Assume that the repair cost of computers follows a normal distribution. Construct a 95% confidence interval for u, the mean repair cost of computers. (a) (70.25, 105.49) (b) (78.49, 121.51) (c) (76.46, 123.54) (d) (57.50, 142.50) (e) (15, 185)