Question: Do middle-aged male executives have different average blood pressure than the general population? The National Center for Health Statistics reports that the mean systolic pressure for males ages 35 to 44 is 128 and the standard deviation of this population is 15. The medical director of a company looks at the medical records of 72 company executives in this age group and finds that the mean systolic blood pressure in this sample is 126.07. Is this evidence that executive blood pressures differ from the national average? Use a 5% level of significance.