EXAMPLE 16 Heights of American Women

The normal curve is a good approximation of the real-life distribution for a variety of biological measures (height, weight, heart rate, blood pressure, and so on), when examined for a particular species and gender. Figure 5.21 shows the heights of American women between the ages of 18 and 24. The proportion of young women who are between 60 inches (5 feet) and 65 inches tall is given by the area under the density curve between 60 and 65. This area is about 0.54, so approximately 54% of these women are between 60 and 65 inches tall.