摘要:

Communicating data without some measure of their precision can lead to misinterpretation and incorrect inferences. Several conventions for displaying error along with the data they modify are described and illustrated. Alternatives are offered that seem to provide improvements in the effective communication of error as well as increasing their ease, and hence their likelihood, of use. These alternatives are illustrated principally with data from the National Assessment of Educational Progress.

ISSN:0003-1305    

DOI:10.1080/00031305.1996.10474355

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This article offers some advice on how to give a presentation, primarily by describing common problems (myths). We hope you will find it is easy to read, and that it will give you some ideas on improving your own presentations.

ISSN:0003-1305    

DOI:10.1080/00031305.1996.10474356

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

It is argued in a Bayesian context in which a set of parameter values is simulated from a prior distribution, that the sampling importance resampling algorithm should not be used to resample these values so as to obtain an approximate sample from the posterior. Rather, the whole set of prior values, along with their appropriate weights, can be more gainfully employed.

ISSN:0003-1305    

DOI:10.1080/00031305.1996.10474357

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Multiple logistic regression coefficients (or the associated odds ratios) alone are not always an adequate basis for making practical and/or scientific interpretations of a model. In this paper I discuss methods for enhancing interpretation through the examination of fitted probabilities. In particular, I focus on analyzing the contribution of specific effects of interest in relation to the background of variation introduced by the other factors in the model.

ISSN:0003-1305    

DOI:10.1080/00031305.1996.10474358

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Many statistical methods involve summarizing a probability distribution by a region of the sample space covering a specified probability. One method of selecting such a region is to require it to contain points of relatively high density. Highest density regions are particularly useful for displaying multimodal distributions and, in such cases, may consist of several disjoint subsets—one for each local mode. In this paper, I propose a simple method for computing a highest density region from any given (possibly multivariate) densityf(x) that is bounded and continuous inx. Several examples of the use of highest density regions in statistical graphics are also given. A new form of boxplot is proposed based on highest density regions; versions in one and two dimensions are given. Highest density regions in higher dimensions are also discussed and plotted.

ISSN:0003-1305    

DOI:10.1080/00031305.1996.10474359

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Pragmatically, is “pooling” worth doing in analysis of variance (ANOVA) tables, statistical niceties aside? The conditions found for pooling to be even potentially rewarding are more restrictive than might be expected, and power improvements are generally poor. Using only elementary arguments and calculations with popular spreadsheets, analyses of standard simple cases show two in which pooling is possibly both sensible and of practical potential benefit: Pooling across sources and pooling of highest and next-to-highest order interaction terms as an error term in the unreplicated 2ndesign case. The special case of paired or unpairedttests is also examined, and the sample correlation needed to make the pairedttest more powerful than the unpaired one is found to be both low and well below conventionally statistically significant values.

ISSN:0003-1305    

DOI:10.1080/00031305.1996.10474360

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In some practical problems where a principal component analysis is utilized, the use of the variance covariance matrix of an appropriately defined set of variables, rather than the correlation matrix, may be more meaningful. This is illustrated through the analysis of 1984 Olympic records data on various track events. The analysis results in conclusions that are more appealing to intuition and that are also consistent with a retrospective visual examination of the data on certain leading countries in their athletic excellence.

ISSN:0003-1305    

DOI:10.1080/00031305.1996.10474361

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The effect of a single variable data point,x, on the usual test statistics for traditional hypothesis tests for means is analyzed. It is shown that an outlier may have a profound and unexpected effect on the test statistic. Although it might appear that an outlier would tend to lend support to the alternate hypothesis, it may in fact detract from the significance of the test. In one-population tests and analysis of variance (ANOVA), the value ofxthat maximizes the significance of the test statistic is given. This value does not have to be unusually large or small. In fact, it often falls within the range of the other sample points. In the general one-population case, the limiting value for the test statistic is shown to be +1. In the case involving more than one population, it is shown that the limiting value of the test statistic is a function only of the number of members in the samples and not their relative values. Special cases are identified in which the test statistic is shown to have unique characteristics depending on the characteristics of the data.

ISSN:0003-1305    

DOI:10.1080/00031305.1996.10474362

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A dangerous trend toward nonrandom sampling mechanisms has been observed in several fields of the applied sciences. These sampling designs are attempts to avoid tail observations, resulting in smaller estimated standard errors and inflated claims of statistical significance. Often, the researchers go to some lengths to make the sampling mechanisms appear random; yet, they clearly are not. The effect of these pseudorandom sampling designs on the power and size of the hypothesis tests is investigated and shown to be substantial.

ISSN:0003-1305    

DOI:10.1080/00031305.1996.10474363

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In this departmentThe American Statisticianpublishes articles, reviews, and notes of interest to teachers of the first mathematical statistics course and of applied statistics courses. The department includes the Accent on Teaching Materials section; suitable contents for the section are described under the section heading. Articles and notes for the department, but not intended specifically for the section, should be useful to a substantial number of teachers of the indicated types of courses or should have the potential for fundamentally affecting the way in which a course is taught.

ISSN:0003-1305    

DOI:10.1080/00031305.1996.10474364

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor