To test the null hypothesis that the mean waist size for males under 40 years equals 34 inches versus the hypothesis that the mean differs from 34, the following data were collected: 33, 33, 30, 34, 34, 40, 35, 35, 32, 38, 34, 32, 35, 32, 32, 34, 36, 30.
Calculate the t* -value of the test statistic.
State the null hypothesis, Ho,and the alternative hypothesis, Ha , that would be used to test the claim: The standard deviation has increased from its previous value of 15.