Suppose the correlation between IQ at age 5 and elementary school performance is +.4, and the correlation between SAT performance and college grades is +.3. The difference in these relationships is most likely due to the fact that
A) the second one is nonlinear
B) the second one has a more restricted range of scores
C) elementary school performance is probably an unreliable measure
D) intelligence declines slightly with age

Question

Quizplus · Accepted Answer

The second relationship has a more restricted range of scores as the SAT is taken only by college-bound students who are a select group, whereas elementary school performance is measured across the general population. This restriction in range reduces the strength of the correlation. Additionally, the SAT-college grade relationship is affected by several intervening variables that are not present in the IQ-elementary school performance relationship, such as motivation, study habits, and teacher quality, which further weaken the correlation.

Suppose the Correlation Between IQ at Age 5 and Elementary