Cholesterol is a fatty substance that is an important part of the outer lining of cells in the body of animals. its normal range for an adult is 120–240 mg/dl. the food and nutrition institute of the philippines found that the total cholesterol level for filipino adults has a mean of 159.2 mg/dl and 84.1% of adults have a cholesterol level below 200 mg/dl. suppose the total cholesterol level is normally distributed. (a) determine the standard deviation of this distribution.
(b) what are the quartiles (the 25% and 75% values) of this distribution?