An illustrative example of a pretest-posttest design with switching replication involves testing an exercise program for depression on two nonequivalent groups: clinical patients and university students. Initially, baseline depression scores are recorded for everyone. The patients then engage in the exercise routine while the students wait, and a second measurement is taken; if effective, only the patients' depression should decrease at this stage. Afterward, the students also begin the exercise program while the patients maintain it. A final assessment should then demonstrate a reduction in the students' depression, confirming the intervention's efficacy across two distinct populations.