摘要:

We propse methods for the detection of outliers in structured populations in the multinomial model under different working hypotheses.

ISSN:0266-4763    

DOI:10.1080/02664769300000011

出版商:Carfax Publishing Company    

年代:1993

数据来源: Taylor

摘要:

The ideas of influence are now well known, and influence functions have been investigated widely, especially in the contexts of regression analysis and multivariate analysis. However, there seems to be no published account of the influence of single observations on simple one-sample tests for means and variance. The usual test statistics, based on normality assumptions, for a mean when the variance is known, and for the variance, display an obvious behaviour when an extra observation is added to a data set. However, the t-test for a single mean has a more interesting, and less predictable, pattern of behaviour. The t-statistic also demonstrates how the theoretical influence function can sometimes be misleading when used to estimate the effect of inserting or deleting a single observation.

ISSN:0266-4763    

DOI:10.1080/02664769300000012

出版商:Carfax Publishing Company    

年代:1993

数据来源: Taylor

摘要:

Genetic algorithms are a set of algorithms with properties which enable them to efficiently search large solution spaces where conventional statistical methodology is inappropriate. They have been used to find effective control and design strategies in industry, for finding rules relating factors and outcomes in medicine and business, and for solving problems ranging from function optimization to identification of patterns in data. They work using ideas from biology, specifically from population genetics, and are appealing because of their robustness in the presence of noise and their ability to cope with highly non-linear, multimodal and multivariate problems. This paper reviews the current literature on genetic algorithms. It looks at ways of defining genetic algorithms for various problems, and examples are introduced to illustrate their application in different contexts. It summarizes the different aspects which have been, and continue to be, the focus of research, and areas requiring further invetigation are identified.

ISSN:0266-4763    

DOI:10.1080/02664769300000013

出版商:Carfax Publishing Company    

年代:1993

数据来源: Taylor

摘要:

An extension of the Gibbs model is proposed in order to analyse circular data distributed on a finite number of concentric circles. This model is used to study the angular distribution of the primary roots of maize around the stem, each internode being modelled as a circle. The roots on a single internode or on two successive internodes interact, the interaction between roots on a single internode being higher than that between roots on two successive internodes.

ISSN:0266-4763    

DOI:10.1080/02664769300000014

出版商:Carfax Publishing Company    

年代:1993

数据来源: Taylor

摘要:

Program 7M in the BMDP statistical package carries out Fisher's linear discriminant analysis and offers a number of options including stepwise variable selection and jack-knife cross-validation. If these two options are used in combination, then a difficulty arises. A Monte Carlo demonstration was performed to demonstrate the problem. The results showed that the classification performance of the stepwise technique under jack-knife appeared to improve when pure noise variables were added to the data set. After studying the manual, it was hypothesized that this phenomenon was due to the stepwise variable selection phase of the procedure being conducted before the jack-knife, rather than being subject to it. This was verified by a second Monte Carlo experiment which compared the jack-knife in BMDP with a complete jack-knife, in which the variable selection phase of the procedure was also subject to the jack-knife.

ISSN:0266-4763    

DOI:10.1080/02664769300000015

出版商:Carfax Publishing Company    

年代:1993

数据来源: Taylor

摘要:

In this paper we examine the effect of the abolition of capital punishment on the homicide rate in Great Britain. Previous studies have used econometric techniques to determine whether the death penalty exerts a significant deterrent effect. However, econometric studies have been severely criticized for failing to provide robust results. The method of investigation used in this paper is that of intervention analysis. Some questions are raised about the proper way to measure the intervention effect in integrated models subject to trend changes. However, for both England and Wales, and for Scotland, a statistically significant intervention effect is consistently detected, although the extent of the effect is difficult to determine precisely. We also examine the effect of several ‘social stress indicators' (e.g. suicide and unemployment rates and violent crime) upon the homicide rate.

ISSN:0266-4763    

DOI:10.1080/02664769300000016

出版商:Carfax Publishing Company    

年代:1993

数据来源: Taylor

ISSN:0266-4763    

DOI:10.1080/02664769300000017

出版商:Carfax Publishing Company    

年代:1993

数据来源: Taylor