The Difference $\bar { X } _ { A } - \bar { X } _ { G }$

Multiple Choice

The difference . $\bar { X } _ { A } - \bar { X } _ { G }$ in a two-factor between-subjects analysis of variance reflects the

A) main effect of factor A plus sampling error
B) main effect of factor B plus sampling error
C) effect of the interaction of factors A and B plus sampling error
D) within-cells error variation