计量抽样率 variable fraction sampling: 分段变量抽样法sampling fraction: 抽样百分率; 抽样比率; 抽样成数; 抽样分数; 抽样份额; 取样率; 样本分数variable sampling: 变动抽样法; 变量抽样;可变抽样法optimum sampling fraction: 最优抽样比overall uniform sampling fraction: 统一抽样比下载手机词典可随时随地查词查翻译