Barrons AP Psychology 7th edition

(E) Approximately 95 percent of the population scores between 70 and 130 on the WISC. The
WISC has a mean of 100 and a standard deviation of 15, which means that the scores between 70
and 130 represent all the scores within two standard deviations of the mean. By definition, in a
normal distribution, about 95 percent of scores fall within two standard deviations of the mean.