statistics
posted by Anonymous .
The heights of American women aged 18 to 24 are normally distributed with a mean of 66 inches and a standard deviation of 2.5 inches. In order to serve in the U.S. Army, women must be between 57 inches and 79 inches tall. What percentage of women are ineligible to serve based on their height?

http://davidmlane.com/hyperstat/z_table.html
That is a pretty powerful applet to check your answers.