Modeling and Fitting Two-Way Tables Containing Outliers

A model is proposed for two-way tables of measurement data containing outliers. The two independent variables are categorical and error-free. Neither missing values nor replication is present. The model consists of the sum of a customary additive part that can be fit using least squares and a part t...

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Main Author: David L. Farnsworth
Format: Article
Language:English
Published: Hindawi Limited 2023-01-01
Series:International Journal of Mathematics and Mathematical Sciences
Online Access:http://dx.doi.org/10.1155/2023/6352058
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author David L. Farnsworth
author_facet David L. Farnsworth
author_sort David L. Farnsworth
collection DOAJ
description A model is proposed for two-way tables of measurement data containing outliers. The two independent variables are categorical and error-free. Neither missing values nor replication is present. The model consists of the sum of a customary additive part that can be fit using least squares and a part that is composed of outliers. Recommendations are made for methods for identifying cells containing outliers and fitting the model. A graph of the observations is used to determine the outliers’ locations. For all cells containing an outlier, replacement values are determined simultaneously using a classical missing-data tool. The result is called the adjusted table. The inserted values are such that, when a mean-based fitting of the adjusted table is performed, the residuals in those cells are zero. The outlying portion of the observation in each of those cells is the difference of the observation and the replacement value. In this way, outliers are removed from further analyses of the adjusted table. This is particularly helpful because outliers can greatly contaminate and alter computations and conclusions. Subsequently, the causes of the outliers might be determined, and statistical estimation and testing can be implemented on the adjusted table.
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spelling doaj.art-f9f6d66b7b9044b88858a80c699e8b462023-02-20T01:57:52ZengHindawi LimitedInternational Journal of Mathematics and Mathematical Sciences1687-04252023-01-01202310.1155/2023/6352058Modeling and Fitting Two-Way Tables Containing OutliersDavid L. Farnsworth0School of Mathematical SciencesA model is proposed for two-way tables of measurement data containing outliers. The two independent variables are categorical and error-free. Neither missing values nor replication is present. The model consists of the sum of a customary additive part that can be fit using least squares and a part that is composed of outliers. Recommendations are made for methods for identifying cells containing outliers and fitting the model. A graph of the observations is used to determine the outliers’ locations. For all cells containing an outlier, replacement values are determined simultaneously using a classical missing-data tool. The result is called the adjusted table. The inserted values are such that, when a mean-based fitting of the adjusted table is performed, the residuals in those cells are zero. The outlying portion of the observation in each of those cells is the difference of the observation and the replacement value. In this way, outliers are removed from further analyses of the adjusted table. This is particularly helpful because outliers can greatly contaminate and alter computations and conclusions. Subsequently, the causes of the outliers might be determined, and statistical estimation and testing can be implemented on the adjusted table.http://dx.doi.org/10.1155/2023/6352058
spellingShingle David L. Farnsworth
Modeling and Fitting Two-Way Tables Containing Outliers
International Journal of Mathematics and Mathematical Sciences
title Modeling and Fitting Two-Way Tables Containing Outliers
title_full Modeling and Fitting Two-Way Tables Containing Outliers
title_fullStr Modeling and Fitting Two-Way Tables Containing Outliers
title_full_unstemmed Modeling and Fitting Two-Way Tables Containing Outliers
title_short Modeling and Fitting Two-Way Tables Containing Outliers
title_sort modeling and fitting two way tables containing outliers
url http://dx.doi.org/10.1155/2023/6352058
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