列联表分析中的Simpson悖论问题

对于分类数据,列联表无疑是最好的统计工具之一,但列联表分析也会带来Simpson悖论问题。从理论上来说,可以通过改变试验结构来消解Simpson悖论,但社会研究数据大多是观测数据,是无法通过试验来控制的,因此Simpson悖论与其说是＂悖论＂,不如说是反映了分类数据的非线性特征,是＂不可压缩＂而压缩的结果,反映了列联表从高维压缩至低维时的统计信息差异,实质上是欧氏空间的降维问题。     

Birds as biodiversity indicators for Europe

It is a truism that biodiversity is vital. It is, after all, a measure of life on earth. It is of more pressing concern that biodiversity is being lost at a rate unprecedented in the recent era, and will continue to be lost unless action is taken. There is species loss and habitat loss across ecosystems from the Arctic icecap to tropical rainforest: the so-called Fifth Great Extinction of species really does seem to be happening. Richard Gregory looks at the role birds can play in measuring biodiversity.     

异方差White检验应用的几个问题

White检验通常由LM检验来完成,现实中也可以使用更简单的F检验来替代LM检验;White检验过程中需要构筑辅助回归模型,它可以有不同的形式以应对实际问题的需要;讨论了四类不同的辅助回归模型,理论分析表明,它们在应用中各有所长;最后通过一个实际例子,验证了理论分析的结论,展示了White检验应用的灵活性。     

Reliability of indices of industrial production in developing countries:the case of Zambia, 1980–89

This paper describes problems met in the calculation of the new index of industrial production in Zambia. It discusses deficiencies of the old index and measures taken to remedy the situation. Comparison of the indices shows that the old index was very unreliable. The average error for most indices was as large, or larger, than their average year-to-year change. Thus it was almost impossible to distinguish real movements in the old index from error variations. Similar problems were found in other developing countries. It is likely that many indices currently in use in these countries are also unreliable.This paper describes problems met in the calculation of the new index of industrial production in Zambia. It discusses deficiencies of the old index and measures taken to remedy the situation. Comparison of the indices shows that the old index was very unreliable. The average error for most indices was as large, or larger, than their average year-to-year change. Thus it was almost impossible to distinguish real movements in the old index from error variations. Similar problems were found in other developing countries. It is likely that many indices currently in use in these countries are also unreliable.This paper describes problems met in the calculation of the new index of industrial production in Zambia. It discusses deficiencies of the old index and measures taken to remedy the situation. Comparison of the indices shows that the old index was very unreliable. The average error for most indices was as large, or larger, than their average year-to-year change. Thus it was almost impossible to distinguish real movements in the old index from error variations. Similar problems were found in other developing countries. It is likely that many indices currently in use in these countries are also unreliable.This paper describes problems met in the calculation of the new index of industrial production in Zambia. It discusses deficiencies of the old index and measures taken to remedy the situation. Comparison of the indices shows that the old index was very unreliable. The average error for most indices was as large, or larger, than their average year-to-year change. Thus it was almost impossible to distinguish real movements in the old index from error variations. Similar problems were found in other developing countries. It is likely that many indices currently in use in these countries are also unreliable.     

Broken-Link Reports from SFX Users: How Publishers,Vendors and Libraries Can Do Better

This study analyzes more than 400 SFX broken-link reports sent by users of an academic library. It raises technical issues regarding OpenURL linking in the handling of special journal volume and issue numbers, journal supplemental issues, embargo release dates, book reviews, DOIs, and other areas. It reports on full-text resources with the most broken links, causes of broken links, and the library's responses to users. It also explores how journal publishers, database vendors, and OpenURL vendors can improve the quality of their products and how librarians can better serve users.     

On optimality of a two-stage sawpling method for binomial populations

We consider a family of two-stage sampling methods for a binomial parameter that guarantee a certain precision. It is shown that, among all such methods, one due to Birnbaum and Healy minimizes the average expected second stage sample size with respect to a certain density on the parameter space. It does not, however, minimize the average expected second stage sample size with respect to the uniform density.     

More maximum likelihood oddities

It is shown that the maximum likelihood estimator is superior to the method of moments in estimating the parameter of triangular distributions. It is also shown that the former is not as difficult to calculate as it was previously perceived—thanks to some of its peculiar properties.     

Optimal Allocation of Observations for Inference on k Ordered Normal Population Means

The optimal allocation of observations when there is a natural ordering in the k normal population means is discussed. It is shown that the design which minimizes the total mean square error of the maximum likelihood estimators in the null case allocates half the observations to each of the two extreme populations. The design is obviously optimal for testing the homogeneity of means against the simple ordered alternative. It is, however, hardly acceptable for the estimation in the nonnull case. It is, therefore, shown that the observations could be allocated to the non-extreme populations according to weights which are proportional to the absolute values of the Abelson and Tukey scores at the same time keeping the minimum local power for testing the simple ordered alternative to be maximal. The design gives also the maximum minimum power, not local, for the alternative in the class of linear tests. It, of course, suffers from a small loss of efficiency for the estimation under the null case but is much better under the nonnull case than the extreme design which allocates half the observations to each of the two extreme populations. Some numerical comparisons of the mean square errors are given.     

基于多源数据融合的个人信用评分研究

随着信息技术的发展,数据来源越来越多,一方面可以更加精准、科学地刻画个人信用状况,但另一方面,由于数据来源多、结构复杂等问题,对传统的征信技术带来了挑战。本文提出了基于多源数据融合的个人信用模型,可以同时对多个数据集进行建模和变量选择,同时考虑了数据集间的相似性和异质性。通过模拟实验发现,本文所提出的整合模型在变量选择和分类效果方面都具有明显的优势。最后,将整合模型应用于城市和农村两个数据集的个人信用评分中。     

Category Distinguishability and Observer Agreement

It is common in the medical, biological, and social sciences for the categories into which an object is classified not to have a fully objective definition. Theoretically speaking the categories are therefore not completely distinguishable. The practical extent of their distinguishability can be measured when two expert observers classify the same sample of objects. It is shown, under reasonable assumptions, that the matrix of joint classification probabilities is quasi-symmetric, and that the symmetric matrix component is non-negative definite. The degree of distinguishability between two categories is defined and is used to give a measure of overall category distinguishability. It is argued that the kappa measure of observer agreement is unsatisfactory as a measure of overall category distinguishability.     

Broken-Link Reports from SFX Users: How Publishers,Vendors and Libraries Can Do Better

Abstract

This study analyzes more than 400 SFX broken-link reports sent by users of an academic library. It raises technical issues regarding OpenURL linking in the handling of special journal volume and issue numbers, journal supplemental issues, embargo release dates, book reviews, DOIs, and other areas. It reports on full-text resources with the most broken links, causes of broken links, and the library's responses to users. It also explores how journal publishers, database vendors, and OpenURL vendors can improve the quality of their products and how librarians can better serve users.     

Locally best invariant test for outliers in a gamma type distribution

It is shown that the locally best invariant test for the existence of outliers for scale parameters of the gamma distribution is given by Bartholomew's test for exponentiality which is the ratio of the sum of squares of the data to the square of the sample mean. The optimality robustness, including null and nonnull robustness of the test is shown. A small simulation study to compare the power among the other eight competitive tests for testing exponentiality is performed. It is seen that the locally best invariant test is not always best but is reasonably good. It is slightly better than Cochran's test and suffers less from the limiting masking effect.     

Why use arbitrary points scores?: ordered categories in models of educational progress

Much statistical modelling of random effects on ordered responses, particularly of grades in educational research, continues to use linear models and to treat the responses through arbitrary scores. Methodological and software developments now facilitate the proper treatment of such situations through more realistic generalized random-effects models. This paper reviews some methodological comparisons of these approaches. It highlights the flexibility offered by the macro facilities of the multilevel random-effects software MLwiN. It considers applications to an analysis of primary school educational progress from reception to England and Wales national curriculum key stage 1 mathematics. By contrasting the results from generalized modelling and scoring approaches it draws some conclusions about the theoretical, methodological and practical options that are available. It also considers that results of generalized random-model estimation may be more intelligible to users of analytical results.     

从政治算术到大数据分析

本文首先对大数据进行了再认识,包括如何理解大数据的“大”、如何理解大数据的“数据”以及大数据是不是好数据;然后对数据的变化与统计分析方法的发展进行了较为系统的历史梳理,对两者的关系进行了总结;最后探讨了统计学的新发展--大数据分析问题,认为大数据分析是数据科学赋予统计学的新任务,指出了大数据分析面临的挑战与突破口,提出了大数据分析需要达成的共识。     

Preserving Electronic Scholarship for the Future: An Overview of LOCKSS,CLOCKSS, Portico,CHORUS, and the Keepers Registry

Electronic resources are becoming the backbone of many library collections. Electronic journals in particular have become the default format for most periodical literature in all fields of scholarship. The mission of librarians, the publishing industry, and nonprofit organizations is to ensure that electronic scholarship remains accessible to future generations in an affordable and sustainable manner. The focus for the first edition of “In Layman's Terms” is on LOCKSS, CLOCKSS, CHORUS, Portico, and the Keepers Registry, five initiatives dedicated to the preservation and to the perpetual access of electronic scholarship. It includes a brief history of each initiative. It looks at their missions and their different roles in preserving and providing access to electronic resources and the benefits and costs in joining them and being involved with them. It identifies the relationships among these initiatives.     

中国特色人力资源价值计量统计模式的构建

一、构建人力资源价值计量统计模式的思路　　 1 人力资源价值是可以计量的人力资源就是人力资产。它具有资产的特性。在人力资源形成、使用和产出效益的过程中 ,是可以用货币来计量的。2 人力资源价值应反映其当期的价值量研究人力资源价值如果只考虑未来的价值 ,是无法确定其价值的 ,因为人力资源未来可能创造的价值具有很大的不确定性 ,无法计量。如果以人本身能力大小、智力高低来确定人力资源的价值是不现实的 ,就人本身而言 ,具有相同条件的人 ,由于思想意识和精神因素不一 ,也不可能相同 ,就是同一个人在不同时期的精神因素也不尽相…     

Dettori Day

It was the day at the races the bookies want to forget. September 28th, 1996, was the one day that dreams came true for punters—they made a killing and, for once, went home richer than the bookmakers. It was the day that Frankie Dettori rode all seven winners at Ascot. Jenny Docherty describes the day's events.     

Comments on the special issue of communications in statistics (vol.a8, no. 10) concerned with weather modification experiments

As stated by the Editors of the Special Issue. It was complied with reference to two of my statements; that much of the current weather modification literature is slanted and unreliable. and(2) that progress in the building of a reliable weather modification technology requires an interdisciplinary study of as many completed cloud seeding experiments as possible. The material published in the Special Issue relates to two completed experiments, the Tasmania and the Israeli experiments. It is shown that a realistic appraisal of a completed experiment requires a prolonged effort, including an examination of quite a few relevant publications and, on occasion, Some numerical work on published raw data. It appears that an interdisciplinary reanalysis of the Tasmania experiment can contribute to the development of a reliable cloud seeding technology.     

含非随机缺失数据的面板数据参数估计方法

抽样调查领域常采用对多个受访者进行跟踪调查得到面板数据,进而对总体特性进行统计推断,在面板数据中常含缺失数据,大多数处理面板缺失数据的软件都是直接删去含缺失值的受访者以得到完全数据集,当数据缺失机制为非随机缺失时会导致总体参数估计结果有偏。本文针对数据缺失机制为非随机缺失情形下,如何对面板数据进行统计分析进行了阐述,主要采用的是基于模型的似然推断法,对目标变量、缺失指示变量和随机效应向量的联合分布建模,在已有选择模型和模式混合模型的基础上,引入随机效应,研究目标变量期望的计算方法,并研究随机效应杂合模型下参数的估计方法,在变量分布相对简单的情形下给出了用极大似然法推断总体参数的估计步骤,最后通过模拟分析比较方法的优劣。     

重视样本普查在我国农业普查中的应用

重视样本普查在我国农业普查中的应用单文豪ＡＢＳＴＲＡＣＴＩｔｉｓｄｉｆｉｃｕｌｔｔｏａｑｕｉｆｅｒｔｈｅａｌｉｎｆｏｒｍａｔｉｏｎｎｅｅｄｅｄｆｏｒｏｕｒｇｏｖｅｒｎｍｅｎｔｉｎｍａｎ－ａｇｉｎｇｍａｃｒｏｅｃｏｎｏｍｙｂｙｆｕｌｙｒｅｌｙｉｎｇｏｎ...