Regression to the mean
Students who scored extremely high on a test tend to score lower (closer to average) on a retest, even with no intervention. What best explains this?
Show hints (2)+
- Decompose each score into true ability plus fresh noise.
- What does conditioning on an extreme observation imply about the noise term?
Answer
Reveal answer →Final answer
Imperfect test–retest correlation pulls extreme scores back toward the mean (a selection-plus-noise effect).
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