在5个城市作整群分层随机抽样调查确定与事故倾性有关指标的正常值范围。
The normal value range of indicators about accident proneness were detected according to epidemiological survey results using stratified random cluster sampling in 5 cities.
方法：分阶段分层整群随机抽样调查。
Methods. The survey was conducted according to multi-stage stratified cluster sampling method.
方法根据全国第四次结核病流行病学抽样调查方案，采用分层整群随机抽样方法抽取调查点，然后根据调查结果进行分析。
Methods According with the methods of the forth epidemiologic sampling survey for tuberculosis in our country, the method of stratified cluster random sampling was use in this survey.
方法根据全国第四次结核病流行病学抽样调查方案，采用分层整群随机抽样方法抽取调查点，然后根据调查结果进行分析。
Methods According with the methods of the forth epidemiologic sampling survey for tuberculosis in our country, the method of stratified cluster random sampling was use in this survey.
应用推荐