Suppose the mean height for men is 70 inches with a standard deviation of 2 inches. What percentage of men are less than 66 inches tall?

Answer 1

If the mean is 70 and the standard deviation is 2, then 66 is 2.0 standard deviations below the mean. Since heights are normally distributed, we can calculate (or look up) the percentage of the population which is below 2 standard deviations from the mean. If you are using a TI-84 calculator, you would key in: 2nd,VARS, 0, 68, 70, 2 ENTER, and you would get an answer: .158655... which means 15.87%.