A.兩樣本均數(shù)相等 B.兩總體均數(shù)相等 C.兩總體均數(shù)不相等 D.兩樣本均數(shù)差別無統(tǒng)計(jì)學(xué)意義 E.兩總體均數(shù)差別無統(tǒng)計(jì)學(xué)意義
A.n1+n2, B.n11n2,-1 C.n1+n2,+1 D.n1+n2,-2 E.n1+n2,+2
A.已知A藥與B藥均有效 B.不知A藥好還是B藥好 C.已知A藥不會(huì)優(yōu)于B藥 D.不知A藥與B藥是否均有效 E.已知A藥與B藥均有效