Over the Course of a Year-Long 2 (Depression: Depressed, Control)

Multiple Choice

Over the course of a year-long 2 (depression: depressed, control) by 2 (therapy: video game therapy, none) experiment, the stock market crashed! Baseline measurements showed people who were initially depressed (mean = 7.5) were significantly more depressed than non-depressed participants (mean = 3.5) . By the end of the study, the researchers concluded that video game therapy was not an effective treatment for depression because there were no differences between therapy (mean = 6.0) and control (mean = 6.0) conditions. Based on this example, what other potential factors are likely to have influenced these results? (circle all that apply)

A) history
B) testing
C) instrumentation
D) regression toward the mean
E) none of the above