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.A researcher conducted a semester-long experiment comparing two instructional programs in math.During the administration of tests during the semester, the researcher found that about ten percent of the experimental group and about five percent of the control group were absent for each administration.

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