抽样

Through compared with the difference of the sampling inspection's OC curves between existent and nonexistent inspection error by utilizing grouping method, we get the conclusion that all the traditional methods are designed on the premise that there is none inspection error exist, so it would terribly depress the probability of acceptance and couldn't veritably reflect the quality of the lot for inspection, if the inspection error is exist when sampling inspecting.

同时通过对集团检验错误存在与否的抽样检验特征曲线的比较，指出：以往的集团抽样检验方案设计，都是在假设无检验误差前提下设计的，在抽样检验中，若存在检验错误，会严重影响抽样检验的接收概率，使抽样检验结果不能客观地反映检验批的质量。

Based on the precision and the cost of the relationship between the use of conditional extremum for the function of several variables method to determine when the first sample for sampling with probability proportion to size,the second-simple random sampling,the two-stage sampling is optimal allocation.

本文根据精度与费用之间的关系，利用求多元函数条件极值的方法，确定当第一级抽样为有放回PPS抽样，第二级抽样为简单随机抽样时，二阶抽样的样本容量最优分配。

Illustrations are used to analyze the limitation of line sampling firstly. For linear limit state, the efficiency of LS is affected by the dispersion of the actual important direction from the optimal one, the bigger the dispersion is, the lower the efficiency is. For non-linear limit state, in case that the actual important direction deviates from the optimal one greatly, the efficiency and the precision of LS decrease seriously, even wrong results are obtained.

首先通过算例分析线抽样方法存在的问题，对于线性问题，线抽样法的效率受抽样重要方向与最优重要方向偏离程度的影响，这种偏离程度越大，效率越低；而对于非线性问题，当抽样重要方向与最优重要方向偏离较大时，线抽样的效率和精度均严重下降，甚至得出错误的计算结果。

Among probability sampling methods, what kinds of research conditions are more appropriate for each sampling method

什麼样的情况下，适合用机率抽样方法简单随机抽样有4种方法：1。简单随机抽样2。分层随机抽样3。系统抽样等距抽样

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。

The survey conducted in Taiwan was designed using a multiple-stage sampling method that utilized the principles of probabilities proportional to size, stratified sampling, and systematic sampling to strengthen the sample's effective representation.

为符合研究的需要，本次研究的抽样方法采取较复杂的多阶段抽样法，主要应用「抽取率与单位大小成比例」原则，结合分层抽样、等距抽样等抽样方法的优点，以求提高样本代表性。

Excepting the conventional methods of surveying samples, such as simple random sampling, stratified sampling, cluster sampling, systematic sampling, liner regression sampling, ratio estimator, two-stage sampling, double sampling, rotate sampling, non-probability sampling, there is sequential sampling and mark-recapture, particularly mark-recapture was introduced in detail.

针对生物资源的调查，除了一般抽样方法如：简单随机抽样、分层抽样、整群抽样、系统抽样、双重抽样、二阶抽样、样本轮换、比率估计、线性回归抽样和不等概抽样，还有序贯抽样和标记-重捕获方法，这里特别详细介绍了标记-重捕获方法。

Simple random sampling; stratification ; ratio and regression estimates; systematic sampling, subsampling; cost functions and choice of optimal design; estimation procedures.

简单随机抽样，分层抽样、比率和回归估计，系统抽样、次级抽样，成本函数与最优设计选择；估计过程。

Firstly,the sampling design has great impact on the accuracy of remote sensing classification.There exists great randomicity on the result of points and cluster sample verification on the different Sampling design.On the same sampling design,the stability of point sample verification is higher than that of Cluster sample verification.Secondly,the average accuracy of different sampling designs of multi-point and multi-cluster sample verification can reflect the accuracy characteristic.During the course of point sample verification,stratified sampling's error is lower than others'.During the course of cluster sample verification,systematic sampling and stratified sampling's accuracy are prior to simple random sampling's.

研究结果表明：（1）抽样方式对遥感分类精度评价结果的影响是客观存在的，不同抽样方式下的点样本和群样本检验结果都存在一定的随机性，但同一种抽样方式下，点样本检验精度评估结果的波动幅度小于群样本检验，稳定性比群样本检验要好；（2）不同抽样方式下的多次点样本和群样本检验的平均精度检验结果基本上都能够反映分类图像的精度特征，其中，点样本检验中，分层随机抽样点样本检验效果较好；群样本检验中，系统抽样群样本检验和分层随机抽样群样本检验的效果优于简单随机抽样群样本检验。

Comparison of statistical and nonstatistical sampling A sample is said to be nonstatistical when the auditors es timate sampling risk by using professional judgment rather than by using sta tistical techniques.

统计抽样与非统计抽样的比较当审计师凭借职业判断而不是运用统计技术来估计抽样风险时，这种抽样就称为非统计抽样。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。