分层抽样

Especially, the combined ratio estimator of domain total is investigated under stratified complemental sampling when auxiliary information can be used.

及该方案在分层抽样下的推广，在有辅助信息可用时构造域总量的分层联合比估计，并给出其方差和方差估计公式，同时我们给出了模拟结果，从模拟结果可以看出，给出的方差估计是估计量方差的近似无偏估计。

By using stratified sampling method, a retrospective analysis was performed according to 1 146 cases.

采用分层抽样的方法，回顾性地分析1 146例患儿首选及联合使用抗生素情况。

Methods: Stratified sampling survey among the youth in government organizations.

研究方法：采用分层抽样方法对机关青年的工作满意度和价值观进行问卷调查。

Methods:Stratified multiple phases sample method was adopted, 240 female doctors were assessed.

采用多阶段分层抽样方法对240名三级甲等综合医院的女性医生进行调查。

In this study, stratified sampling is used to select samples in Gansu Province.

本研究采用分层抽样的方法，在甘肃省四个县进行调查和分析。

Finally to Stratified Sampling improvement of technology put forward some views.

最后对分层抽样技术的改进提出了一些看法。

Methods Based on stratified sampling, 363 medical facilities were selected to conduct the survey.

采取分层抽样方法在全国范围内抽取363家医疗机构开展调查。

Methods A self-developed questionnaire was used to investigate 2600 old persons selected in 26 provinces by stratified sampling.

方法在26省按照城乡和男女分层抽样，对2600名老年人进行问卷调查，并对有效的2414份问卷进行数据统计学处理。

In this paper, 236 SMEs of different types of ownership and from different industries are investigated using a stratified sampling method.

本文采用分层抽样方法，对236家不同所有制、具有行业代表性的中小企业展开了问卷调查。

Stratified sampling design is applied in obtaining an accurate representation of the population by grouping the data into nonoverlapping groups, for example gender or income level, then selecting a simple random sample within each group.

分层抽样是将总体分成若干个组分，在每个组分中进行简单随机抽样，其原则在于将类似的样本归在一个组里面。

If you are unfortunate enough to the lovelorn, please tell me, I will help you out, really, please contact me!

如果你不幸失恋了，请告诉我，我会帮助你摆脱困境，真的，请联系我啦！

China's plan to cut energy intensity by 20 percent and pollutant discharges by 10 percent between 2006 and 2010 is a case in point.

中国计划在2006年到2010间降低20%的能源强度和减少10%的主要污染物排放，就是一个这样的例子。