Questionfor a manturing company wishes to reduce the mean time needed serer visit to a customer location in his region. Nationally, this company sets a standard that a customer service visit should last at most four hours, on average. He is concerned that the service technicians in his region may be violating that standard, so he samples 41 customer service visits. In this sample, the mean time needed for a service visit is 4.2 hours with standard deviation 1.6 hours. In a previous example, we determined that the $t$-test for the mean should be conducted. a. Set up the null and alternative hypothesis to test the regional manager's claim that the standard set by the company is being violated. b. Calculate the value of the test statistic. c. Find the p-value. d. At the $\alpha=0.05$ level of significance, make a decision whether to reject $\mathrm{H}_{0}$. e. Interpret this conclusion.