Exhibit 11-4

Multiple Choice

Exhibit 11-4.Identify the major threat to internal validity in the following research studies.
-Refer to Exhibit 11-4.Students who had low scores on a reading pretest were chosen for a special instructional program.This group showed significant gains on a reading achievement test administered after a period of four months.

A) Regression
B) Diffusion
C) Mortality
D) Selection
E) History