Which of the following threats to internal validity would result in group differences prior to the start of the study?
A)Design confound
B)Selection effect
C)Order effect
D)Maturation effect

Question

Quizplus · Accepted Answer

A selection effect occurs when the groups being compared are already different prior to the start of the study. This could be due to nonrandom assignment or self-selection into groups.

Which of the Following Threats to Internal Validity Would Result