分层抽样

objective to determine the menarche age among female students and the relation between body fat and menarche in anhui province to provide theoretical basis for adopting intervention measure and carrying out health education.methods probability unit regression were used to calculate mmas in 3 000 girls aged 9～18 years old,who were selected from 3 areas in 2005.results mmas were 12.76 and 13.11 years old for urban and rural girls respectively.the youngest age was 10.the menarche age was significantly,related with bmi sebum thickness of abdomen,sebum thickness of shoulder blade and the upper arm.conclusion there was significant relationship between menarche age and body fat.menarche age showed an ahead trend in han national students in anhui province.sex eduction should be conducted in advance,and it was important to strengthen sex education in adolescent.

目的 了解安徽省女生月经初潮及初潮前后体脂变化情况，为采取干预措施和健康教育提供理论依据。方法按照2005年全国学生体质调研要求，采用分层整群抽样方法，对安徽省南、中、北3个地区城乡9～18岁中小学女生3000人进行调查，并测量体质指数、腹部皮脂厚度、上臂皮脂厚度和肩胛下皮脂厚度4项指标。结果城市女生半数月经初潮平均年龄为12.76岁，农村女生13.11岁，城乡最小月经初潮年龄均为10岁。体质指数、腹部皮脂厚度、上臂皮脂厚度和肩胛下皮脂厚度4项指标均值来潮组均大于未来潮组，差异有统计学意义，p.01。结论月经初潮年龄与体脂因素关系密切；安徽省汉族学生月经初潮年龄呈现提前趋势，性教育应提前，加强青春期性教育尤为重要。

Methods Proportional to Size Sampling method was employed and face to face interview was used to collect the information.

采用分层、三阶段与规模成正比的抽样方法获得调查对象，调查员入户面对面进行问卷调查。

Methods Population Proportional to Size sampling method was employed in sampling.

方法2005年11~12月采用分层、三阶段与规模成正比的容量比例抽样方法获得调查对象，采用统一调查问卷由统一培训的调查员入户进行面对面调查。

Methods The multi stratified grouping random sampling method and the proportional sampling was used.

本次流调方法与全国第四次流调方法基本一致，采用分层整群等比例随机抽样方法。

According to the survey for the whole country to the provinces, autonomous regions and municipalities for the whole meeting, to take layered, multi-stage cluster probability sampling method proportional.

据介绍，这次调查以全国为总体，以各省、自治区、直辖市为次总体，采取分层、多阶段、整群概率比例的抽样方法。

The subjects are 609 students sampled from a junior high school at Taipei County by stratified proportional random sampling method.

本研究以台北县某国中学生为母群体，采分层比例随机抽样方法，抽出样本609人。

Methods Stratified random proportional sampling method was used to interview undergraduate students. Version 3.0 of the Composite International Diagnostic Interview of World Health Organization (WHOCIDI3.0) was applied for investigation.

应用分层按比例随机抽样的方法，采用世界卫生组织复合性国际诊断交谈表3.0(WHOCIDI3.0)对在校本科生进行访谈。

Methods: According to the principle of stratified proportional sampling, a total of 1605 adult subjects from 17 cities and their surrounding rural areas of China was measured by CWVDT.

自编中文字词识别测验，经条目筛选后采用分层比例抽样方法，在全国五个行政区17个大中城市及周边农村抽取样本1605例。

The subjects were selected by the "probability proportional to size" sampling method from Taipei County from February to July 1988. A total of 2,367 mothers of children were questioned in personal and/or telephone interviews. The response rate was 74%.

以等机率分层分段抽样方法，自台北县内选取12至23个月大之幼儿为样本，於民国七十八年一月至七月间，针对幼儿母亲以家庭访视和电话访问方式，共收得2，367位个案资料，完访率达74%。

Probability proportional sampling conducted according to various school sizes was used in this study to select subjects from all school nurses working at the elementary and junior high school levels.

研究采横断性调查法，研究工具为结构式问卷，采邮寄问卷方式以等比例分层随机抽样针对全国各学校单位之学校卫生护理人员进行抽样调查。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。