Cholesterol is a fatty substance that is an important part of the outer lining (membrane) 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 less than 200 mg/dl lwww.fnri.dost.gov.ph/). Suppose that the total cholesterol level is normally distributed. a. Determine the standard deviation of this distribution. b. What are the quartiles (the 25% and 75% percentiles) of this distribution? c. What is the value of the cholesterol level that exceeds 90% of the population? d. An adult is at moderate risk if cholesterol level is more than 1 but less than 2 standard deviations above the mean. What percentage of the population is at moderate risk according to this criterion? e. An adult whose cholesterol level is more than 2 standard deviations above the mean is thought to be at high risk. What percentage of the population is at high risk? f. An adult whose cholesterol level is less than 1 standard deviation below the mean is thought to be at low risk. What percentage of the population is at low risk