粗集在交通事故黑点成因分析中的应用

交通事故黑点的形成原因多种多样,每一个事故多发点都有其形成的最大诱因。作为交通安全管理工作的重要任务,交通事故黑点的鉴别与改善是预防交通事故发生、减少交通事故损失的有效手段。该文针对交通事故多发点成因的复杂性和多样性,提出通过粗集来对公路交通中的不利因素进行筛选,找到形成事故多发点的最大诱因,从而有针对性地进行整治,能够有效地节约时间和费用,避免不必要的人力、物力浪费。     

Generating autocorrelated pseudo-random numbers with specific distributions

An easily implemented and computationally efficient procedure is presented for the generation of autocorrelated pseudo-random numbers with specific probability distributions. A plot illustrates the relationship among the autocorrelations of the uniform, Rayleigh, and exponential distributions corresponding to a given autocorrelation in the normal generating distribution.     

Estimation of the failure rate-a survey of nonparametric methods Part I: Non-Bayesian Methods

In this paper several nonparametric, non-Bayesian methods for estimating the failure rate function on which no monotonicity conditions have been imposed are surveyed. The survey attempts to consolidate and synthesize literature from several diverse areas of application, and endeavors to be as up-to-date as is feasible.     

中国生命表中终寿年成数的经验估计

本文讨论了终寿年成数的意义和它的一般特征 ,提出了确定终寿年成数的精确方法 ,计算了中国生命表中终寿年成数的经验值     

Stepwise canonical analysis in categorical data

Assignment of optimum scores to the categories of a multidimensional contingency table by use of a stepwise method of canonical correlations for more than two vector variables is proposed and illustrated for the well-known blood serological data of Taylor, first analyzed by Fisher. This stepwise method provides a technique for eliminating categories that do not contribute significantly to the relationship.     

A Bootstrap Approach for Testing Marginal Independence Between Two Categorical Variables When Subjects Have Repeated Responses

To assess independence in two-way contingency tables, the Pearson chi-square test or Fisher’s exact test are typically used. These tests assume that each subject contributes at most one count to only one table cell (e.g., sex versus blood type). In other situations, each subject may have more than one count contributing to the table and these counts may occur in different cells of the table. One may wish to test independence, adjusting for the within-subject correlation. We provide a simple nonparametric bootstrap approach and assess its performance through simulation studies. The method is illustrated on subjects with multiple mental health presentations to Emergency Departments.     

Measure of departure from symmetry for the analysis of collapsed square contingency tables with ordered categories

For square contingency tables with ordered categories, there may be some cases that one wants to analyze them by considering collapsed tables with some adjacent categories combined in the original table. This paper considers the symmetry model for collapsed square contingency tables and proposes a measure to represent the degree of departure from symmetry. The proposed measure is defined as the arithmetic mean of submeasures each of which represents the degree of departure from symmetry for each collapsed 3×3 table. Each submeasure also represents the mean of power-divergence or diversity index for each collapsed table. Examples are given.     

The asymptotic covariance structure of log-linear model estimated parameters for the multiple recapture census

This paper presents a matrix formulation for log-linear model analysis of the incomplete contingency table which arises from multiple recapture census data. Explicit matrix product expressions are given for the asymptotic covariance structure of the maximum likelihood estimators of both the log-linear model parameter vector and the predicted value vector for the observed and missing cells. These results are illustrated for data pertaining to a population of children possessing a common congenital anomaly.     

乒乓球比赛中打高球的有效战术与训练探析

乒乓球比赛中打好高球具有特别的意义。在打高球的过程中,要注意保证准确性,掌握和控制主动权,保持良好的心态、坚决果断,采用快慢杀相结合、压反手调正手和重、轻、长、短相结合的有效战术。在训练中要练好扎实的正手攻球技术,要练为战。赛前要进行有针对性的场地适应性训练。     

Partitioning Pearson's Chi-squared Statistic for Singly Ordered Two-way Contingency Tables

This paper presents a partition of Pearson's chi-squared statistic for singly ordered two-way contingency tables. The partition involves using orthogonal polynomials for the ordinal variable while generalized basic vectors are used for the non-ordinal variable. The benefit of this partition is that important information about the structure of the ordered variable can be identified in terms of locations, dispersion and higher order components. For the non-ordinal variable, it is shown that the squared singular values from the singular value decomposition of the transformed dataset can be partitioned into location, dispersion and higher order components. The paper also uses the chi-squared partition to present an alternative to the maximum likelihood technique of parameter estimation for the log-linear analysis of the contingency table.