A.所需的樣本量愈小B.所需的樣本量愈大C.不影響樣本量大小D.樣本量的估計(jì)愈準(zhǔn)確E.樣本量的估計(jì)愈不準(zhǔn)確
A.空白對(duì)照B.歷史對(duì)照C.標(biāo)準(zhǔn)對(duì)照D.安慰劑對(duì)照E.實(shí)驗(yàn)對(duì)照
A.歷史對(duì)照B.空白對(duì)照C.標(biāo)準(zhǔn)對(duì)照D.安慰劑對(duì)照E.自身對(duì)照