An experimenter finds that students in a morning class perform better on a math test after being taught with a new teaching method compared with students in an afternoon class who are taught with a standard teaching method. He concludes that the new teaching method is superior to the old method. The main problem with this experimenter's conclusion is:

Question

Quizplus · Accepted Answer

The main problem with the experimenter's conclusion is that he did not consider the time of day that students were being taught. This could be a confounding variable, as it is possible that the morning class performed better simply because they were more awake and alert than the afternoon class. Therefore, it is not appropriate to conclude that the new teaching method is superior without controlling for this variable.

An Experimenter Finds That Students in a Morning Class Perform