短語詞組短語stratified multistage cluster sampling 分層多級整群抽樣stratified random cluster sampling 群分層隨機抽樣stratified and cluster sampling 採用分層整群抽樣方法Stratified cluster random sampling 分層整群隨機抽樣stratified cluster sampling technique 分層抽樣技術(shù)stratified cluster sampling method 分層整群抽樣方法stratified sampling and cluster sampling 分層整群抽樣stratified one stage cluster sampling 分層一級整群抽樣stratified one -stage cluster sampling 分層單級整群抽樣 返回 stratified cluster sampling