stratified sampling造句

1、Methods With stratified sampling and cluster sampling, we investigate 487 families in poverty.
方法采用分层整群抽样方法调查487户贫困家庭。

2、Stratified sampling can reduce the sampling error associated with simple random samples.
分层抽样可以减少由简单随机抽样造成的抽样误差。

3、Methods: The stratified sampling and cluster random sampling methods are used in this survey.
方法：本研究采用分层随机抽样方法和整群随机抽样方法。