成组设计的方差分析中,必然有

A、[img=~/QImg/2013-10-14-10-49-09/image048.jpg]
B、[img=~/QImg/2013-10-14-10-49-09/image049.jpg]
C、[img=~/QImg/2013-10-14-10-49-09/image050.jpg]
D、[img=~/QImg/2013-10-14-10-49-09/image051.jpg]
E、[img=~/QImg/2013-10-14-10-49-09/image052.jpg]