ISSN:0007-1102    

DOI:10.1111/j.2044-8317.1995.tb01055.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Although the Johnson‐Neyman problem has been well defined in the literature, computational problems have restricted its use by researchers. The computational problems can be simplified considerably by defining the analysis of covariance model in terms of the general linear model in which the contrast matrix for assessing group effects holds the unknown values to which groups are equated. A solution for the unknown values or boundary for the region of significance can be obtained by using the symbolic processing, or three‐dimensional graphing and contour plotting capabilities of the Mathematica computer software pack

ISSN:0007-1102    

DOI:10.1111/j.2044-8317.1995.tb01056.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

There are a variety of exploratory and informal graphical methods for studying the relationship between two random variables, many of which offer some resistance to outliers or unusual values. Some of these are extremely flexible when considering how the mean ofYmight be related to some other random variable,X. However, when interest is focused on a resistant measure of location, such as the trimmed mean or a robust M‐estimator of location, the choice of methods is considerably reduced, and some of the more obvious procedures can fail. When dealing with how a measure of scale associated withYvaries as a function ofX, even fewer methods arc available. This paper suggests a simple exploratory procedure that can be used to study how any parameter associated withYvaries as a function of Moreover, this is done without imposing any restrictions on what the relationship might be. The method might be used to suggest an appropriate transformation of the data, to summarize data without imposing any parametric restrictions, and in some cases the method suggests pursuing an investigation where more standard techniques (correlation and least squares regression) suggest that there is nothing interesting in the data. This latter feature is illustrated with data from a study on when a child utters its first wor

ISSN:0007-1102    

DOI:10.1111/j.2044-8317.1995.tb01057.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0007-1102    

DOI:10.1111/j.2044-8317.1995.tb01058.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY