SUPP 3.5.Low values of HDL (high-density lipoprotein) have been found to be associated with increased risk of heart disease. Assume that HDL levels in a population of women (ages 20 years or more) are approximately normally distributed with mean mu= 55 mg/dL and standard deviation sigma=15.5 mg/dL.

a) Find the percent of women who are considered to have a protective level of HDL, which is 60 mg/dL or greater.