Approximately what percentage of the population is likely to score above 145 or below 55 on an intelligence test?
A) 10 percent
B) 68 percent
C) 50 percent
D) one-tenth of 1 percent (0.1%)

Question

Quizplus · Accepted Answer

The percentage of the population scoring above 145 or below 55 would fall beyond 3 standard deviations from the mean in a normal distribution, which accounts for about 0.1% of the population. This is also known as the "extreme" or "outlier" range. Choices A, B, and C are incorrect as they are too high and do not reflect the rarity of scores in this range.

Approximately What Percentage of the Population Is Likely to Score