The statistical phenomenon that causes a group's average performance on one measure to appear closer to the mean of that measure at the second measurement is referred to as a(n)____ threat.
A)history
B)mortality
C)instrumentation
D)regression

Question

Quizplus · Accepted Answer

This phenomenon is referred to as regression to the mean, which occurs when there is random error in the first measurement causing extreme scores to move closer to the mean upon a second measurement. Choices A, B, and C refer to different threats to validity, but do not adequately describe this particular phenomenon.

The Statistical Phenomenon That Causes a Group's Average Performance on One