Question

Empirical Rule 06

IQ scores can be described using a Normal distribution with a mean of 100 and a standard deviation of 15.
Using the Empirical '68-95-99.7' Rule, what percent of IQ scores are above 130?

Answer 1

The Empirical Rule, also known as the 68-95-99.7 rule, states that for a normal distribution, approximately 68% of the data lies within one standard deviation of the mean, 95% lies within two standard deviations, and 99.7% lies within three standard deviations.

In this case, the mean is 100 and the standard deviation is 15, so approximately 95% of the data lies within two standard deviations of the mean. Since two standard deviations of 100 is 30 (15 * 2), this means that approximately 95% of the data lies within the range of 70 to 130. Therefore, approximately 5% of the data lies outside of this range, with 2.5% lying below 70 and 2.5% lying above 130.

Therefore, the percent of IQ scores that are above 130 is approximately 2.5%.