对中学生自发的抽样知识的调查研究

对抽样知识的理解是统计素养的基础，而抽样方法是抽样知识的重要组成部分．中学生在没有学抽样知识前就表现出了统计学上常用的几种抽样方法萌芽．总体上，他们在抽样过程中对随机性缺乏认识，认识不到随机样本的统计公平性，而更相信分层抽样，而且不同年级、不同层次水平的学生对抽样知识的认识也存在差异。     

5ayes统计中两种抽样法的比较分析

拒绝性抽样法和重要性抽样法是贝叶斯统计中两种重要的产生模拟样本的方法．两种方法之间存在一些关联,拒绝性抽样法在做一些形式上的转变后可以看作一种特殊的重要性抽样法．此外,如果将拒绝性抽样法中的包络函数作为重要性抽样法中的提议密度函数,这样新形成的抽样法会比原本的拒绝性抽样法更为有效．     

大气采样技术研究

在空气环境污染物的监测中,采样是整个监测过程的第一步,是监测工作的重要环节.采样方法正确与否,关系到监测结果的可靠性和准确性.为此,采样人员在采样前必须进行误差分析,定期校准采样器,对采样系统进行气密性检查,按时校准流量,掌握程序的设置方法.最后,采集后安全及时送回实验室内分析.     

时间取样观察法的优缺点及其适用性问题

关于社会行为发展的研究大都采用时间取样观察法。该方法用于估计实际行为出现的次数、频率和持续时间以及测量群体或个体的差异。但许多研究表明，时间取样观察法存在着一些不足与局限，如时间取样法不能精确地估计行为的频率和持续时间；对个体或群体差异的测量不准确等。而且，有些研究是不适合用时间取样观察法的。因此如果所取样的行为持续时间很短的话，研究可以选择更为有效的观察法，如事件取样观察法、顺序取样法等来进行研究。     

湖南电大开放教育试点毕业生追踪调查抽样设计

湖南电大开放教育试点专业毕业生追踪调查的抽样遵循随机性、分布相对均匀性、行业代表性等基本原则,采取分层等距抽样的方法。抽样根据湖南电大开放教育毕业生实际情况适当扩大了调查范围和抽样比例,确定的本专科专业抽样层数量扩大到24个,毕业生样本数扩大到1975个,用人单位样本数扩大到1342个,样本总数达到3317个,为较全面的掌握全省试点教育实施情况提供了信息支撑。     

教育研究的抽样问题——有目的抽样

教育研究常常遇到抽样的问题，而我们阐述较多的是如何使用随机抽样以保证教育研究的科学性。对使用较多的有目的抽样则阐述较少。本以随机抽样的局限性为引子，集中对教育科研中有目的抽样的含义、变式、以及如何应用做了初步的探讨，以期引起研究的重视。     

浅谈问卷调查中非抽样误差的控制

问卷调查是采用抽样调查方式，利用设计好问题的表格，收集数据资料并对其进行统计分析的一种调查方法，但问卷调查的结果常常会受到抽样误差和非抽样误差的影响，尤其是后一般难以控制。因此，研究各个阶段非抽样误差的成因，采取不同措施分别加以控制就十分必要。     

组合投资规模与风险关系研究中抽样设计问题的解决

本文研究了传统组合投资规模与风险关系实证研究中抽样设计的缺陷，包括不同规模单一组合的无放回逐一组合随机抽样相对放回组合随机抽样的缺陷，不同规模多次组合的组合标准差放回简单随机抽样相对无放回简单随机抽样的缺陷。在此基础上，给出了组合标准差放回和无放回简单随机抽样样本容量的确定公式。最后，文章通过实证研究验证了上述结论     

A Comparison of Item Sampling Plans in the Application of Multiple Matrix Sampling

This study used a Monte Carlo approach to investigate the effect of item sampling by item stratification on parameter estimation when applying multiple matrix sampling to achievement data. From the results of this study it was concluded that the item sampling method and sampling plan which is a practical compromise in terms of precision and sample size is one based on item stratification by item discrimination and a sampling plan with a moderate number of subtests. This sampling condition provides reasonable precision of the mean and variance estimates but requires only a moderately sized sample.     

Time sampling: a methodological critique

Numerous developmental studies of social behavior employ an observational technique called time sampling. This technique is used to estimate the frequencies and proportions of time that actual behaviors occur and to measure group or individual differences. By contrasting time sampling to continuous sampling, we demonstrate that (a) time sampling is inaccurate for estimating actual durations or frequencies of behavior, and (b) resulting individual and/or group differences can change depending on whether time sampling or continuous sampling is used. Error rates are particularly high when the total bout lengths of the actual behaviors are short (as in mother-infant interactions) and/or when interval length is long. Because the majority of mother and infant behaviors are short in bout length (less than 60 sec), when percent error is the greatest, we suggest that alternative sampling methods that have proven validity be used in future studies (e.g., scan, point, or continuous sampling).     

简单随机抽样中几个问题的探讨

介绍了与简单随机抽样有关的一些概念和这种抽样方式的若干特点,指出了统计教材中对简单随机抽样论述的欠缺,接着对简单随机抽样中的若干难点如每个单位的入样概率是相等的、抽样中的随机原则和如何用随机数字表进行简单随机抽样等进行了探讨.     

The Use of Multiple Matrix Sampling for Survey Research

Multiple matrix sampling procedures can be employed to improve survey research when the results of matrix sampling are equivalent to those obtained by the traditional census testing approach. This study examined the use of multiple matrix sampling as a strategy for the collection of data and compared rates of response when subgroups of items were administered as opposed to an entire instrument. In addition, the study investigated whether responses were equivalent in the two sampling procedures and whether bias was present. The results indicate that multiple matrix sampling is a viable and reasonable procedure to use when a mail survey questionnaire consists of a large number of pages and/or items.     

基于DDS技术的高速等效采样示波器设计

为了更好地实现对高频周期信号的采样,设计了基于DDS技术高速等效采样的数字示波器,以不大于1 MHz的实时采样率实现了最高2.5 GHz的等效采样率。系统电路以CycloneIII FPGA芯片为核心,结合外围器件,完成了测量频率范围10 Hz～15 MHz,输入信号范围2 mV～16 V,水平显示分辨率25点/div,垂直灵敏度包括2 V/div、2 mV/div共10档可调,实时采样与等效采样相结合的数字存储示波器。本设计电路结构简单,以低速AD实现了高速信号的采集,实现方案新颖。     

Biased sampling activity: an investigation to promote discussion

The statistical concept of sampling is often given little direct attention, typically reduced to the mantra “take a random sample”. This low resource and adaptable activity demonstrates sampling and explores issues that arise due to biased sampling.     

A MONTE CARLO STUDY OF ITEM SAMPLING (VERSUS TRADITIONAL SAMPLING) FOR NORM CONSTRUCTION1

Using a computer-based model of an item trace line, a random sampling experiment concerned with comparing item sample estimates to traditional (examinee) sample estimates of the mean and variance of a distribution of test scores was conducted. The results indicated that the optimal method for estimating a test's parameters may depend on several conditions. As expected, item sampling proved superior to traditional sampling in estimating test means under all conditions. However, with certain test lengths, ranges of item difficulty, and discrimination, traditional sampling provided better estimates of test variance than did item sampling.     

基于LabVIEW的抽样定理仿真研究

与连续时间信号相比,离散时间信号的处理更加灵活、方便,应用更加广泛。在实际应用中,通常先将连续时间信号转换成离散时间信号,前提是抽样过程必须满足抽样定理。抽样定理在连续时间信号与离散时间信号之间架起了一座桥梁。本文利用LabVIEW对抽样过程进行仿真,并对抽样定理的条件与结论进行验证和讨论,通过研究可以得到符合实际应用的结论,同时加深对抽样定理的理解和把握。     

AN APPLICATION OF ITEM-EXAMINEE SAMPLING TO SCALING ATTITUDES

The post mortem item-examinee sampling investigation described herein explored the feasibility of using item-examinee sampling to estimate scale values denoting degree of affect toward stimuli when measured by the method of paired-comparisons. Results indicate that such scale values can be approximated satisfactorily through item-examinee sampling. Defining one observation as the response made by one examinee to one item, the similarity between the estimated scale values and normative scale values increased generally with increases in the number of observations acquired by the sampling plan.     

新鲜植株碳氮素的快速分析及其应用

本文提出了植株碳氮素的快速分析法 ,并对水稻碳氮素代谢进行了研究。结果表明 :不仅分析方法快速、准确 ,而且用在研究水稻碳氮代谢 ,在探明不同时间采样、不同部位采样、施肥前后采样、不同生育阶段采样、不同器官采样等方面的碳氮变化规律均获满意结果 ,最后还总结出以营养诊断为目标的采样分析方法。     

AN EXPERIMENTAL COMPARISON OF ITEM SAMPLING AND EXAMINEE SAMPLING FOR ESTIMATING TEST NORMS

An empirical comparison of the accuracy of item sampling and examinee sampling in estimating norm statistics. Item samples were composed of 3, 6, or 12 items selected from a total test of 50 multiple-choice vocabulary questions. Overall, the study findings provided empirical evidence that item sampling is approximately as effective as examinee sampling for estimating the population mean and standard deviation. Contradictory trends occurred for lower ability and higher ability student populations in accuracy of estimated means and standard deviations when the number of items administered increased from 3 to 6 to 12. The findings from this study indicate that the variation of sequences of items occurring in item sampling need not have a significant affect on test performance.     

电流互感器取油样连接阀的研制

对于顶珠式放油阀的电流互感器,取样时靠人工顶住顶珠取油,既操作不便且样本不准确,同时在不停电取样时容易因感应电造成人身伤害,为此研制了一种取样连接阀.经实践验证,这种简便、灵活、实用的电流互感器取油样阀,克服了以上取样的不足.