Cholesterol Levels. According to the National Health and Nutrition Examination

Survey, published by the Centers for Dis-ease Control and Prevention, the average cholesterol

level for children between 4 and 19 years of age is 165 mg/dL. A pediatrician who tested the

cholesterol levels of several young patients was alarmed to find that many had levels higher than

200 mg/dL. The following relative-frequency histogram shows the readings for some patients

who had high cholesterol levels.

Use the graph to answer the following questions. Note that cholesterol levels are always

expressed as whole numbers.

a) What percentage of the patients have cholesterol levels be-tween 205 and 209, inclusive?

b) What percentage of the patients have levels of 215 or higher?

c) If the number of patients is 20, how many have levels between 210 and 214, inclusive?