Hypothesis test for the population mean: Z test. A furniture store claims that a specially ordered product will take, on average, 28 days (4 weeks) to arrive. The standard deviation of these waiting times is 5 days. We suspect that the special orders are taking longer than this. To test this suspicion, we track a random sample of 26 special orders and find that the orders took a mean of 29 days to arrive. Assume that the population is normally distributed. Can we conclude at the 0.01 level of significance that the mean waiting time on special orders at this furniture store exceeds 28 days? Perform a one-tailed test.