A group of researchers conduct a study where children from particular classrooms are assigned to treatment or control conditions. After the study, the researcher finds out that the students in the control group are higher achievers than those in the experimental group. He found no treatment effect. The failure to find a treatment effect might be due to:
A) A treatment effect
B) A testing effect
C) A differential selection effect
D) A maturation effect

Question

Quizplus · Accepted Answer

The failure to find a treatment effect might be due to a differential selection effect, where the control and experimental groups were not equivalent at the start of the study, leading to biased results.

A Group of Researchers Conduct a Study Where Children from Particular