The National Center for Health Statistics reports that the average systolic blood for males 35-44 years of age has a mean of 121. The medical director of a large company believes the average systolic blood pressure for male executives 35-44 years of age at his company is different from 121. He asks for male executives in this age range to volunteer to participate in his study. He looks at the medical records of the 81 volunteers and finds that the mean systolic blood pressure in this sample is 127.2 with a standard deviation of 28. Assume the population distribution is normal. The medical director conducts a hypothesis test. Are all the assumptions met?