摘要:

Various methods for clustering mixed-mode data are compared. It is found that a method based on a finite mixture model in which the observed categorical variables are generated from underlying continuous variables out-performs more conventional methods when applied to artificially generated data. This method also performs best when applied to Fisher's iris data in which two of the variables are categorized by applying thresholds.

ISSN:0266-4763    

DOI:10.1080/02664769000000001

出版商:Carfax Publishing Company    

年代:1990

数据来源: Taylor

摘要:

Non-linear functional relationships between two variables (curve fitting with errors in both variables) may be defined in a similar way to linear functional relationships. The ratio of the error variances must be fixed to obtain a solution to the likelihood equations, but this solution may not be unique. The best fitting solution may change abruptly as the error variance ratio passes through a critical value. Some examples are given.

ISSN:0266-4763    

DOI:10.1080/02664769000000002

出版商:Carfax Publishing Company    

年代:1990

数据来源: Taylor

摘要:

This paper describes a consultancy problem where the question was to compare the variability of two groups of plants using several variables of widely differing types. The two-stage approach adopted is uncommon, and may be more generally useful to any analysis where variables are not commensurate. The Appendix describes the measures of similarity used within the paper, and the important result (equation 4) that gives the squared distances of a set of points from their centroid.

ISSN:0266-4763    

DOI:10.1080/02664769000000003

出版商:Carfax Publishing Company    

年代:1990

数据来源: Taylor

摘要:

In the context of the general linear modelY=Xβ+ε, the matrixPz=Z(ZTZ)−1ZT, whereZ=(X: Y), plays an important role in determining least squares results. In this article we propose two graphical displays for the off-diagonal as well as the diagonal elements ofPZ. The two graphs are based on simple ideas and are useful in the detection of potentially influential subsets of observations in regression. SincePZis invariant with respect to permutations of the columns ofZ, an added advantage of these graphs is that they can be used to detect outliers in multivariate data where the rows ofZare usually regarded as a random sample from a multivariate population. We also suggest two calibration points, one for the diagonal elements ofPZand the other for the off-diagonal elements. The advantage of these calibration points is that they take into consideration the variability of the off-diagonal as well as the diagonal elements ofPZ. They also do not suffer from masking.

ISSN:0266-4763    

DOI:10.1080/02664769000000004

出版商:Carfax Publishing Company    

年代:1990

数据来源: Taylor

摘要:

In a previously published study, the effects of rounding on the significance and power of four test statistics were considered when the parent population was normal. Here we investigate how these tests will perform for rounded non-normal data. Guidelines are given on how the degree of precision recommended for normal populations can be applied when the population is non-normal.

ISSN:0266-4763    

DOI:10.1080/02664769000000005

出版商:Carfax Publishing Company    

年代:1990

数据来源: Taylor

摘要:

This paper discusses inference regarding the mean direction and the concentration parameters based on data from the von Mises distribution from a Bayesian point of view, when k(k < n/2) of the n observations are spurious, that is, are from a von Mises population with a shifted mean direction. The Bayesian analysis for this spuriosity case provides both detection, identification, and estimation for the mean direction and the concentration parameter when indeed spurious observations are present, possibly giving rise to outliers.

ISSN:0266-4763    

DOI:10.1080/02664769000000006

出版商:Carfax Publishing Company    

年代:1990

数据来源: Taylor

摘要:

This paper discusses resolvable row-column designs for v treatments arranged in b blocks each comprising pq units further grouped into p rows and q columns. A resolvable row-column design has v =pqs treatments set out in r groups of s blocks. Each rectangular block has p rows and q columns.

ISSN:0266-4763    

DOI:10.1080/02664769000000007

出版商:Carfax Publishing Company    

年代:1990

数据来源: Taylor

摘要:

The problem of constructing simultaneous confidence intervals for various measures of association is considered. Alternative bootstrap algorithms are given for approximating the sampling distributions of the quantities generating the confidence sets. The small sample performance of the procedures is illustrated using simulated data from 3- and 6-variate normal populations. The results are applied to a large multidimensional longitudinal data set from a study of the relationship between drug use and several behavioral attributes.

ISSN:0266-4763    

DOI:10.1080/02664769000000008

出版商:Carfax Publishing Company    

年代:1990

数据来源: Taylor

摘要:

It is of particular importance to nurse manpower planners to determine the likelihood and time-scale of return to service of nurses who have temporarily withdrawn from the labour force. Such behaviour is common in female dominated professions and is referred to in the nursing literature as being in ‘limbo’. In this paper we develop non-parametric, parametric and network models to describe the distribution of stay in ‘limbo’ and estimate the probability of return to service. These models are fitted to data from the Northern Ireland nursing service. It is inherent in the problem that the data are statistically incomplete. This must be taken into account in the statistical methods used to estimate the various model parameters.

ISSN:0266-4763    

DOI:10.1080/02664769000000009

出版商:Carfax Publishing Company    

年代:1990

数据来源: Taylor

摘要:

The use of single group skewness and kurtosis critical values for the assessment of residual normality in the ANOVA model is examined. Using single group critical values gives a conservative test of residual normality in multiple group designs. As the sample size per group increases, the empirical Type I error rates for the skewness and kurtosis tests of residual normality approach a. These results supplement previous work which has focused on testing residual normality in the linear regression model.

ISSN:0266-4763    

DOI:10.1080/02664769000000010

出版商:Carfax Publishing Company    

年代:1990

数据来源: Taylor