A professor was interested in whether caffeine affected test performance. To test this possibility, he gave students a test and asked them whether they had consumed caffeine in the hour before the test. He then compared the performance of those students who had taken caffeine to those who had not. Why is this not a true experiment?

Question

Quizplus · Accepted Answer

The study lacks random assignment to groups, which is a necessary component of a true experiment to ensure that groups are equivalent and any differences in performance can be attributed to the manipulation of the independent variable (in this case, caffeine consumption).

A Professor Was Interested in Whether Caffeine Affected Test Performance