The Main Problem Associated with Subject Attrition During the Course

Multiple Choice

The main problem associated with subject attrition during the course of a study is that

A) groups initially created to be equivalent may no longer be equivalent.
B) the group with the most participants remaining at the end of a study will likely have higher posttest scores.
C) the researcher can no longer use statistical analysis to understand the results.
D) regression to the mean on the dependent variable measure is likely.