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

Multiple Choice

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.