两样本均数比较时,样本含量公式为

A、[img=~/QImg/2013-10-14-11-12-39/image042.jpg]
B、[img=~/QImg/2013-10-14-11-12-39/image043.jpg]
C、[img=~/QImg/2013-10-14-11-12-39/image044.jpg]
D、[img=~/QImg/2013-10-14-11-12-39/image045.jpg]
E、以上都不对