Question: The serum-cholesterol levels of a group of people who eat primarily macrobiotic diet are measured. Among 60 of them, ages 20-40, the mean cholesterol level was found to be 186 mg/dL with a standard deviation of 36 mg/dL.

The mean cholesterol level in the general population in this age group is 221 mg/dL, and the distribution is assumed to be normal. Using significance level 0.05, test the hypothesis that the people on a macrobiotic diet have cholesterol levels that are lower than those from the general population. State your hypothesis and conclusions. Give the p-value.