Managers at an automobile manufacturing plant would like to examine the mean completion time, μ, of an assembly line operation. The past data indicate that the mean completion time is 43 minutes, but the managers have reason to believe that this value has changed. The managers plan to perform a statistical test. After choosing a random sample of assembly line completion times, the managers compute the sample mean completion time to be 44 minutes. The standard deviation of the population of completion times can be assumed not to have changed from the previously reported value of 4 minutes. Based on this information, answer the questions below. What are the null hypothesis (H0) and the alternative hypothesis (H1) that should be used for the test?

H0: μ is
H1: μ is

In the context of this test, what is a Type II error?

A Type II error is the hypothesis that μ is when, in fact, μ is .

Suppose that the managers decide not to reject the null hypothesis. What sort of error might they be making?