Match the research examples in 1-7 with the main threat to internal validity that it contains (a-g).
-A psychiatrist selects a group of patients with the most extreme symptoms of depression. After one month of therapy, the patients have markedly improved.
A) Maturation
B) History or environmental events
C) Repeated testing
D) Instrumentation
E) Selection or assignment
F) Mortality or attrition
G) Statistical regression

Question

Quizplus · Accepted Answer

The improvement in patients with the most extreme symptoms of depression after therapy can be attributed to statistical regression, where extreme scores (or symptoms, in this case) tend to move towards the mean (average) over time, especially in a subsequent measurement. This phenomenon suggests that the observed improvement might not solely be due to the therapy but also to the natural tendency of extreme cases to regress towards the mean.

Match the Research Examples in 1-7 with the Main Threat