Question

239. In a normal distribution of IQ scores, what percentage of people has a

score between 85 and 115?
(A) 35 percent
(B) 54 percent
(C) 68.26 percent
(D) 79.32 percent
(E) 95.44 percent

Answer 1

In a normal distribution of IQ scores, approximately 68.26% of people have a score between 85 and 115, corresponding to one standard deviation above and below the average IQ of 100 with a standard deviation of 15. The correct option is C.

Step-by-step explanation:

In a normal distribution of IQ scores, the percentage of people that have a score between 85 and 115 is 68.26 percent.

This is because, in a normal distribution, approximately 68% of the data falls within one standard deviation of the mean. Since the average IQ score is 100 and the standard deviation is 15 points, a score between 85 (one standard deviation below the mean) and 115 (one standard deviation above the mean) would encapsulate roughly 68% of the population, as mentioned in Figure 7.15.

Therefore, the correct answer to the question is (C) 68.26 percent.