短語(yǔ)詞組短語(yǔ)cluster systematic random sampling method 束系統(tǒng)隨機(jī)抽樣方法Stratified cluster random sampling 分層整群隨機(jī)抽樣cluster random sampling method 整群隨機(jī)抽樣方法multi -stage random cluster sampling 群抽樣random cluster sampling 整群抽樣stratified random cluster sampling 群分層隨機(jī)抽樣random and cluster sampling 隨機(jī)整群抽樣 返回 cluster random sampling