A lawn and garden sprinkler system is designed to have a delayed start; that is, there is a delay from the moment it is turned on until the water starts. The delay times form a normal distribution with mean 45 seconds and standard deviation 8 seconds. Several customers have complained that the delay time is considerably longer than claimed.The system engineer has selected a random sample of 15 installed systems and has obtained one delay time from each system. The sample mean is 50.1 seconds. Using a = 0.02 is there significant evidence to show that the customers might be correct that the mean delay time is more than 45 seconds?
a. Solve using the p-value approach.
b. Solve using the classical approach.