Question

The scale of scores for an IQ test are approximately normal with mean 100 and standard deviation 15. The organization MENSA, which calls itself the “high IQ society”, requires a score of 130 or higher. What percent of adults are between IQ of 100 and 130 ?

A)68%
B)47.5%
C)95%
D)81.5%

Answer 1

B) 47.5%

Explanation:

Refer to the normal distribution chart attached. If 130 is 2 standard deviations higher than the mean (ignore the numbers beneath the percentages), then by the empirical rule, this means that 34%+13.5%=47.5% of adults are between IQs of 100 and 130. Therefore, option B is correct.