分层抽样

The estimation of population mean is obtained using a cluster sampling method with supplementary stratified sample.

针对这一缺陷，提出了一种辅以分层抽样样本的整群抽样方案，得到了总体均值的估计量，以及这一估计量的一些良好性质。

Objective To know the existing conditions, influence factors of country women's puerperal dietary and to study scientific puerperal dietary and health care pattern.

目的了解农村妇女产褥期饮食习惯的现状及影响因素，探讨其科学的饮食方式和保健模式。方法采取分层抽样与整群抽样相结合的方法，对湖北麻城县农村712名妇女产褥期的饮食状况进行回顾性问卷调查。

Applying mathematical statistics, this paper studied the characters of random sampling and its excessive random effect on other trip characters, put forward stratified sampling method, researched quota sampling and best distribution sampling.

建议对于大型城市采用简单随机抽样方法；而对于中小城市，按年龄分类，采用分层抽样方法，以提高调查精度。

A 1∶250 00 standard map sheet (about 91 km 2) is used as a sampling unit in the western China's Xinjiang Uygur Autonomous Region and one county is used as a sampling unit in eastern China.

在黄淮海、长江中下游棉区采用县为单元的分层抽样的方法，抽样样本用遥感调查的方法获得。

Stratified random sampling and simple random sampling methods were used to select sample from 14 counties.

通过分层抽样和单纯随机抽样相结合的方法，抽取昆明市14个县的部分参合农民进行问卷调查。

Methods The integration of simple random sampling and stratified sampling was adopted to select 480 soldiers of 5 different branches of the military forces stationed in Jinan as study objects.

采用简单随机抽样和分层抽样相结合的方法抽取驻济5个兵种不同的部队，计480名军人作为研究对象。

In chapter 4 based above two chapters, we disscuss sampling method of supplemented sample under both cluster sample and stratified sample having auxiliary information.

已有的 分层抽样和整群抽样方案都有自己的使用范围，在不适合的情况下使用效率很低。

Moreover, I extend the sampling problems from one population to two or more subpopulation.

并且由单一母体的简单随机抽样，扩展到分层抽样的问题。

15 hospitals and 2 937 residents were selected and studied through random and systematic sampling methods in Hainan Province.

采用分层抽样和随机抽样方法对15家医疗机构和2 937名疟区居民进行流行病学调查。

We made use of the methods of stratified sampling and random sampling to investigate 269 882 broth prescriptions of Medical Department of TCM in 21 various hospitals, 18 provinces, and constructed the database, then applied Weka KDD software to analyze.

在全国不同区域，选取18个省市的21家医院，采用分层抽样和简单随机抽样相结合的方法，收集门诊中医内科内服汤剂处方269 882张，构建中药饮片用量数据库，基于Weka数据挖掘软件进行统计分析。

Since historical times,England ,where the early inhabitants were Celts, has been conquered three times .

从有历史以来，英国，在此地早期居住的是凯尔特人，已经被征服了三次。

Bluetooth OBEX File Transfer Enables the sending and receiving of files on your phone via Bluetooth.

蓝牙OBEX文件移动允许经过蓝牙传送和接受文件。。。。