Hypothesis testing of single mean.
Last month the mean waiting time at the drive through window of a fast-food restaurant was 3.7 minutes. The franchise has installed a new course intended to reduce waiting time. After an installation, a random sample of 64 orders is selected. The sample mean waiting time is 3.57 minutes with a sample standard deviation of 0.8 minutes. At a 5 percent level of meaning, is there sufficient evidence that the population mean waiting time is now less than 3.7 minutes?