The Difference Between Before-After and Controlled Before-After Experimental Design Is

Multiple Choice

The difference between before-after and controlled before-after experimental design is that the _____.

A) controlled before-after design is meant specifically for primary research
B) before-after design is meant specifically for primary research
C) controlled before-after design involves not one group, but two
D) before-after design eliminates the possibility of other variables influencing the results
E) before-after design measures the variables to be tested before the experiment begins