Cholesterol Levels. According to the National Health and Nutrition Examination Survey, published by the Centers for Disease 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 relativefrequency histogram shows the readings for some patients who had high cholesterol levels.

0.0 0.1 0.2 0.3 0.4 195 Cholesterol level (mg/dL)

Relative frequency 200 205 210 215 220 225 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 between 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?