Web‐based resources to assist the statistical analysis and presentation of data

The intention of this article is to highlight sources of web‐based reference material, courses and software that will aid statisticians and researchers. The article includes websites that: assist in writing a protocol or proposal; link to online statistical textbooks; and provide statistical calculators or links to free statistical software and other guidance documents. Copyright © 2005 John Wiley & Sons, Ltd.     

Effective Microcomputer Statistical Software

This article focuses on important aspects of microcomputer statistical software. These include documentation, control language, data entry, data listing and editing, data manipulation, graphics, statistical procedures, output, customizing, system environment, and support. The primary concern is that a package encourage good statistical practice.     

A Note on the Variances of the Tests of Kendall,Jonckheere, and Terpstra

Recently, some papers have been appearing that have noticed some mistakes in the calculations in the statistical software in simple and classical tests (Wilcoxon–Mann-Whitney and Log-Rank). This article examines the variance formulas for the Kendall test, the Jonckheere test, and the Terpstra test. We show in this article that these variances (in spite of what is said in the literature and in the statistical software), in the presence of ties and r ≥ 3 groups, are only equal approximately and are exactly equal for two groups and ties as we prove in the Appendix.     

Some Uses for Distribution-Fitting Software in Teaching Statistics

Statistics courses now make extensive use of menu-driven, interactive computer software. This article presents some insight as to how a new class of PC-based statistical software, called “distribution-fitting” software, can be used in teaching various courses in statistics.     

多指标综合评价中主成分分析和因子分析方法的比较

文章通过对主成分分析和因子分析在研究目的、分析原理、SPSS软件实现过程方面的比较,指出在多指标综合评价时应用两种方法应该注意四个问题,以正确地进行实证研究。     

统计调查数据的全面质量管理

本文借鉴全面质量管理体系的概念,综合分析贯穿统计工作整个流程的统计调查数据质量管理的要素及作用。本文重点讨论了全面质量管理的流程和重点工作的布局;结合统计信息化的建设,特别讨论了相关工作规范、应用软件的作用,以及数据资源的建设和利用。     

Comparing two clinical measurements: a linear mixed model approach

In this article, we extended the widely used Bland-Altman graphical technique of comparing two measurements in clinical studies to include an analytical approach using a linear mixed model. The proposed statistical inferences can be conducted easily by commercially available statistical software such as SAS. The linear mixed model approach was illustrated using a real example in a clinical nursing study of oxygen saturation measurements, when functional oxygen saturation was compared against fractional oxy-hemoglobin.     

Developing a Career in the Practice of Statistics: The Mentor's Perspective

The W.J. Dixon Award for Excellence in Statistical Consulting is given by the American Statistical Association to “a distinguished individual who has demonstrated excellence in statistical consulting or developed and contributed new methods, software, or ways of thinking that improve statistical practice in general.” In this article, five of the seven past recipients of this career-capping award share their experiences and perspectives through 10 stepping stones that move a practicing statistician from consultant to collaborator to leader. We highlight the need for mentorship throughout the discussion, and provide direction for statisticians who would like to incorporate this advice into their careers.     

Likelihood Maximization Using Web-Based Optimization Tools

This article proposes the use of optimization techniques and tools to maximize the likelihood if maximization cannot be easily accomplished with standard statistical software. In such situations, the use of the programming language AMPL with the freely available optimization solvers under the NEOS Server is an attractive alternative to algorithms developed for specific optimization problems in statistics. This article is meant to be a short tutorial introducing statisticians to these methods and tools. We provide an example to illustrate these methods. The necessary files for maximization are included in the Appendix so that the reader can carry out the optimization procedure described.     

大学生数学成绩影响因素的实证分析

伴随着近几年高校的扩大招生,部分大学生的数学成绩显著下降。用统计学软件SPSS 13.0对哈尔滨工程大学部分学生的高等数学成绩及其相关因素进行统计分析,考察学生的高考数学成绩、性别、生源所在地等因素对其大学数学成绩的影响。在给出了一些切实可行的对策和建议的同时,指出培养大学生学习的主动性和研究探索精神,已经成为当今高校教师和教育工作者培养高素质人才和提高教学水平的关键。     

Statistical Tools on the World Wide Web

The World Wide Web (WWW) represents a powerful tool for furthering the development and practice of statistics. The GASP (Globally Accessible Statistical Procedures) WWW site has been set up as a primary listing of statistical procedures which can be used over the WWW. This article highlights several possible approaches for making a procedure WWW accessible. These approaches effectively solve many of the problems typically encountered when using a new statistical procedure. Applying the methods discussed, any statistical technique can be made available to anyone with a forms- or Java-capable WWW browser. Procedures can be delivered in a virtually platform-independent manner with only minimal requirements on a user's hardware or software.     

Performing Legitimate Parametric Regression Analysis without Knowing the True Underlying Random Mechanisms

Real data are rarely normally distributed. Nonetheless, regression analysis is routinely done under the assumption of normality. Such a practice generally results in invalid statistical inferences once normality is false.

This article shows how one could carry out corrected normal regression and gamma regression analysis, which provides asymptotically valid inferences without the knowledge of the true underlying distributions. No additional programming is necessary in order to implement the proposed novel regression method. Outputs provided by existing statistical software suffice.     

A Comparative Review of Nonparametric Statistics Textbooks

ABSTRACT

In this article I will review six textbooks commonly set in University undergraduate nonparametric statistics courses. The books will be evaluated in terms of how key statistical concepts are presented; use of software; exercises; and location on a theory-applications axis and an algorithms-principles axis. The placement of books on these axes provides a novel guide for instructors looking for the book that best fits their approach to teaching nonparametric statistics.     

Testing the Existence of Change-Point in NHPP Software Reliability Models

In the software testing process, the nature of the failure data is affected by many factors, such as the testing environment, testing strategy, and resource allocation. These factors are unlikely to all be kept stable during the entire process of software testing. As a result, the statistical structure of the failure data is likely to experience major changes. Recently, some useful non homogeneous Poisson process (NHPP) models with change-point are proposed. However, in many realistic situations, whether a change-point exists is unknown. Furthermore, some real data seem to have two or more change-points. In this article we propose test statistics to test the existence of change-point(s). The experimental results of real data show that our tests perform well.     

Selecting significant effects in factorial designs: Lenth's method versus using negligible interactions

Among the many analytical techniques that have been published to analyze the significance of the effects in the absence of replications, two have emerged as the most widely used in text books as well as statistical software packages: The Lenth's method and the estimation of the variance of the effects from the values of those considered negligible. This article shows that neither is better than the other in all cases, and by analyzing the results obtained in a wide variety of situations it provides guidelines on when it is preferable to use one or the other technique.     

Covariance Analysis for Split-Plot and Split-Block Designs

Commentaries are informative essays dealing with viewpoints of statistical practice, statistical education, and other topics considered to be of general interest to the broad readership of The American Statistician. Commentaries are similar in spirit to Letters to the Editor, but they involve longer discussions of background, issues, and perspectives. All commentaries will be refereed for their merit and compatibility with these criteria.

Proper methodology for the analysis of covariance for experiments designed in a split-plot or split-block design is not found in the statistical literature. Analyses for these designs are often performed incompletely or even incorrectly. This is especially true when popular statistical computer software packages are used for the analysis of these designs. This article provides several appropriate models, ANOVA tables, and standard errors for comparisons from experiments arranged in a standard split-plot, split–split-plot, or split-block design where a covariate has been measured on the smallest size experimental unit.     

A Review of Three Directed Acyclic Graphs Software Packages

This article offers a review of three software packages that estimate directed acyclic graphs (DAGs) from data. The three packages, MIM, Tetrad and WinMine, can help researchers discover underlying causal structure. Although each package uses a different algorithm, the results are to some extent similar. All three packages are free and easy to use. They are likely to be of interest to researchers who do not have strong theory regarding the causal structure in their data. DAG modeling is a powerful analytic tool to consider in conjunction with, or in place of, path analysis, structural equation modeling, and other statistical techniques.     

Statistical Microcomputing—Like it is

A statistical software package is a collaborative effort between a program's authors and users. When statistical analysis took place exclusively on mainframe computers, the entire statistical community was served by some three to six major packages, which helped to ensure that program errors would be quickly uncovered and corrected. The current trend toward performing statistical analysis on microcomputers has resulted in an explosion of software of varying quality, with more than 200 packages for the IBM PC alone. Since all of these programs are competing for the same base of knowledgeable users, the number of sophisticated users per package is dramatically less than for mainframe packages; the net result is that problems in any particular package are more likely to go unnoticed and uncorrected. For example, the most widely used shareware package contains major errors that should cause it to be rejected out of hand, and three best-selling packages analyze unbalanced two-factor experiments using an approximate technique originally developed for hand calculation. Several strategies are offered to help author and user reveal any problems that might be present in their software.     

The SAS Macro-Program %AnaQol to Estimate the Parameters of Item Responses Theory Models

The analysis of quality of life questionnaires is taking a great importance in clinical research. Usual and general statistical packages like SAS do not allow users to perform classical analysis of items or to estimate parameters of most used models in this specific field: the practitioners must use various specific software to analyze a quality of life scale. In this article, we present an easy to use SAS macro-program that enables SAS users to obtain classical indices, usual graphical representations, and estimation of parameters of five usual Item Response models. We illustrate capabilities of our macro-program by presenting some practical real Quality of Life examples.     

Estimation across multiple models with application to Bayesian computing and software development

Statistical models are sometimes incorporated into computer software for making predictions about future observations. When the computer model consists of a single statistical model this corresponds to estimation of a function of the model parameters. This paper is concerned with the case that the computer model implements multiple, individually-estimated statistical sub-models. This case frequently arises, for example, in models for medical decision making that derive parameter information from multiple clinical studies. We develop a method for calculating the posterior mean of a function of the parameter vectors of multiple statistical models that is easy to implement in computer software, has high asymptotic accuracy, and has a computational cost linear in the total number of model parameters. The formula is then used to derive a general result about posterior estimation across multiple models. The utility of the results is illustrated by application to clinical software that estimates the risk of fatal coronary disease in people with diabetes.