a. A statistics practitioner randomly sampled 1,500 observations and found and s  25. Test to determine whether there is enough evidence at the 5% significance level to infer that the population mean is less than 15.

b. Repeat part

(a) assuming that you know that the population standard deviation is   25.

c. Explain why the conclusions produced in parts

(a) and

(b) are virtually identical.

x = 14 x = 103 x = 74.5 x = 350 x = 15,500 x = 175