Third graders who scored in the bottom 20% of a standardized reading test were selected for a study on a new method for teaching reading. At the end of a 9-month test period, the children's scores had improved significantly more than could be expected by chance or by the passage of time. A potential problem with the design of this study is
A) maturation.
B) statistical regression.
C) selection.
D) mortality.

Question

Quizplus · Accepted Answer

Statistical regression refers to the phenomenon where individuals who score extremely low (or high) on a test tend to score closer to the mean on a subsequent test, regardless of any intervention. Since the study selected children who scored in the bottom 20%, their scores are likely to improve towards the mean over time due to statistical regression, not necessarily because of the new teaching method.

Third Graders Who Scored in the Bottom 20% of a Standardized