在R×C表的χ[img=~/QImg/2013-10-14-11-12-39/image001.jpg]检验中,设n[img=~/QImg/2013-10-14-11-12-39/image030.jpg],nc和n分别为行合计,列合计和总计,则计算每格理论数的公式为

A、[img=~/QImg/2013-10-14-11-12-39/image031.jpg]
B、[img=~/QImg/2013-10-14-11-12-39/image032.jpg]
C、[img=~/QImg/2013-10-14-11-12-39/image032.jpg]
D、[img=~/QImg/2013-10-14-11-12-39/image033.jpg]
E、[img=~/QImg/2013-10-14-11-12-39/image034.jpg]