Question

226. On a normal distribution of IQ test scores, with a mean of 100 and a

standard deviation of 15 points, a score of 85 places you approximately in
what percentile of the population?
(A) 16th
(B) 50th
(C) 97th
(D) 76th
(E) 24th

Answer 1

An IQ score of 85 on a normal distribution with a mean of 100 and a standard deviation of 15 places someone in the 16th percentile of the population. The correct option is A.

Step-by-step explanation:

The question is about where an IQ score of 85 would place someone on a normal distribution with a mean of 100 and a standard deviation of 15.

Since 85 is one standard deviation below the mean, we can use the properties of the normal distribution to determine the percentile. Approximately 68% of values lie within one standard deviation above or below the mean, and because the distribution is symmetric, about 34% are between the mean and one standard deviation below.

Therefore, the remaining 50% - 34% = 16% of scores lie below 85. Thus, a score of 85 places someone approximately in the 16th percentile of the population, which corresponds to option (A).