A sociologist asserts that the average length of courtship is long before a second marriage than before a first. He bases this assertion on the fact that the national average for first marriage courtships is 265 days, with a standard deviation = 50.

For his sample of 626 subjects on their second marriage, he finds the average length of courtship to be 268.5 days. Test the validity of his assumption. Solution: The provided sample mean is f = 268.5 and the known population standard deviation is or = 50, and the sample size is n = 626. {1 i l’llull and Alternative Hypotheses The following null…