查询词典 proportional sampling

In this review, historical background of sampling theory and development of forest inventories are presented. Application and research status of sampling methodology and technology in forest inventory in China and abroad are analyzed and reviewed, which includes sampling with probability proportional to frequency or to size, sampling based on remote sensing and sampling for rare population. Finally, both development trends and some problems of sampling methodology are discussed.

本文介绍了抽样理论的发展和国内外森林抽样调查发展过程，论述了森林调查中主要抽样方法的特点和研究现状，其中包括等概和不等概抽样、基于遥感的抽样、针对稀疏总体分布的抽样调查技术方法，并对这些抽样技术在国内外森林资源调查中的应用进行了综述，概括了抽样调查技术方法的发展趋势，最后总结了抽样技术方法还存在的一些问题。

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。

That is sampling 15 percent of total amount, grouping according the code, simple proportional sampling and clustering sampling with group. A core collection bank of ...

按照最佳建库方案构建起了一个以资源总数3170份的15%，即477份核心样品资源可代表总体资源98%以上的遗传多样性的核心种质库。

Small signal equivalent circuit analysis shows that the small signal output resistance in the accurate proportional current sampling mode circuit is much larger than that in a traditional proportional current sampling mode circuit, and circuit stability could be assured.

通过电路的小信号模型分析，得到精密比例采样模式的小信号等效输出电阻远大于传统比例采样模式，同时保证了系统的稳定性。

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。

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。

Methods: The study population was physicians of accredited regional general hospitals in central Taiwan. The amount of samples for all levels hospitals depended on proportional sampling. Totally, 920 copies of questionnaires were issued. Among them, the valid questionnaires were 506 copies and valid response rate was 55%. Data collection was by means of structured questionnaires.

研究对象为中部地区医院评鉴等级为地区级以上综合医院之医师，依比率抽样方式决定各层级医院之样本数，共发出920份问卷，有效问卷共计 506份，有效问卷回收率为 55%，藉由结构式问卷收集资料。

Three methods are adopted to improve the performance of output precision and cross regulation in the multi-output switch mode power supply,including stack wire wound of transformer,output inductance coupling and output proportional sampling.

针对多路输出 DC/DC变换器存在的输出精度与交叉调整率问题，提出了三种改善措施：变压器堆叠绕法、输出电感耦合与输出比例取样反馈，同时给出了设计实例。

The research targets of the study were the grade-six students of public elementary schools in Taipei County, and the survey through questionnaires was done using stratified proportional sampling, with 1,190 valid questionnaires and valid return rate of 92% from all the questionnaires collected.

研究对象为九十五学年度台北县公立国小六年级学童，采分层比例抽样进行调查，回收之有效问卷计1190份。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。