Arakawa Tomoko Inc. has instituted an inventory control policy that calls for severely reduced production if the average age of the units currently in inventory exceeds 120 days. Each month, the company takes a simple random sample of 50 units from its large population of inventoried items in order to evaluate the current situation. The sample mean is used to test the competing hypotheses: H0: μ < 120 days. Ha: μ > 120 days If the test uses a significance level of .05, indicate and explain your decision for each of the following cases:
a. The p value for the sample result is .034.
b. z stat is 2.14.
c. The sample mean is 122.3 days. Assume the population standard deviation is 10.8 days.