Modern tests of intelligence calculate IQ as a deviation score.When this method of reporting is used, the percentage of individuals who have an IQ between 70 and 130 is approximately:
A)68%
B)10%
C)95%
D)50%

Question

Quizplus · Accepted Answer

When IQ is reported as a deviation score, it is based on a normal distribution with a mean of 100 and a standard deviation of 15. This means that approximately 68% of individuals will have an IQ score within one standard deviation of the mean, or between 85 and 115. However, if we want to know the percentage of individuals who have an IQ score between 70 and 130, we need to look at two standard deviations above and below the mean. This encompasses about 95% of the population, making the correct answer C) 95%.

Modern Tests of Intelligence Calculate IQ as a Deviation Score