Experts consider high serum cholesterol levels to be associated with an increased incidence of coronary heart disease. Suppose that the natural logarithm of cholesterol levels for males in a given age bracket is normally distributed with a mean of 5.35 and a standard deviation of .12.
a. What percentage of the males in this age bracket could be expected to have a serum cholesterol level greater than 250 mg/ ml, the upper limit of the clinical normal range?
b. What percentage of the males could be expected to have serum cholesterol levels within the clinical normal range of 150–250 mg/ ml?
c. What percentage of the adult males in this age bracket could be expected to have a very risky cholesterol level— that is, above 300 mg/ ml?