Robust estimator to deal with regression models having both continuous and categorical regressors: a simulation study

The Ordinary Least Squares (OLS) method has been the most popular technique for estimating the parameters of the multiple linear regression. However, in the presence of outliers and when the model includes both continuous and categorical (factor) variables, the OLS can result in poor estimates. In...

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Main Authors: A. Talib, Bashar, Midi, Habshah
Format: Article
Language:English
Published: Universiti Putra Malaysia Press 2009
Online Access:http://psasir.upm.edu.my/id/eprint/16589/1/16589.pdf
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author A. Talib, Bashar
Midi, Habshah
author_facet A. Talib, Bashar
Midi, Habshah
author_sort A. Talib, Bashar
collection UPM
description The Ordinary Least Squares (OLS) method has been the most popular technique for estimating the parameters of the multiple linear regression. However, in the presence of outliers and when the model includes both continuous and categorical (factor) variables, the OLS can result in poor estimates. In this paper we try to introduce an alternative robust method for such a model that is much less influenced by the presence of outliers. A numerical example is presented to compare the performance of the OLS, the Re-weighted Least Squares based on the Robust Distance Least Absolute Value (RLSRDL1), and the Re-weighted Least Squares based on the Robust Distance S/M estimator (RLSRDSM). The latter is the modification of the RDL1. The empirical evidence shows that the performance of the RLSRDSM is fairly close to the RLSRDL1 up to 20% outliers. As the percentage of outliers increases to more than 20%, the RLSRDSM is slightly better than the RLSRDL1. However, the Robust Distance Least Absolute Value (RDL1) estimator posed certain computational problems such as degenerate non-unique solutions while the RLSRDSM do not have such problem.
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spelling upm.eprints-165892015-05-27T07:22:41Z http://psasir.upm.edu.my/id/eprint/16589/ Robust estimator to deal with regression models having both continuous and categorical regressors: a simulation study A. Talib, Bashar Midi, Habshah The Ordinary Least Squares (OLS) method has been the most popular technique for estimating the parameters of the multiple linear regression. However, in the presence of outliers and when the model includes both continuous and categorical (factor) variables, the OLS can result in poor estimates. In this paper we try to introduce an alternative robust method for such a model that is much less influenced by the presence of outliers. A numerical example is presented to compare the performance of the OLS, the Re-weighted Least Squares based on the Robust Distance Least Absolute Value (RLSRDL1), and the Re-weighted Least Squares based on the Robust Distance S/M estimator (RLSRDSM). The latter is the modification of the RDL1. The empirical evidence shows that the performance of the RLSRDSM is fairly close to the RLSRDL1 up to 20% outliers. As the percentage of outliers increases to more than 20%, the RLSRDSM is slightly better than the RLSRDL1. However, the Robust Distance Least Absolute Value (RDL1) estimator posed certain computational problems such as degenerate non-unique solutions while the RLSRDSM do not have such problem. Universiti Putra Malaysia Press 2009 Article PeerReviewed application/pdf en http://psasir.upm.edu.my/id/eprint/16589/1/16589.pdf A. Talib, Bashar and Midi, Habshah (2009) Robust estimator to deal with regression models having both continuous and categorical regressors: a simulation study. Malaysian Journal of Mathematical Sciences, 3 (2). pp. 161-181. ISSN 1823-8343 http://einspem.upm.edu.my/journal/volume3.2.php
spellingShingle A. Talib, Bashar
Midi, Habshah
Robust estimator to deal with regression models having both continuous and categorical regressors: a simulation study
title Robust estimator to deal with regression models having both continuous and categorical regressors: a simulation study
title_full Robust estimator to deal with regression models having both continuous and categorical regressors: a simulation study
title_fullStr Robust estimator to deal with regression models having both continuous and categorical regressors: a simulation study
title_full_unstemmed Robust estimator to deal with regression models having both continuous and categorical regressors: a simulation study
title_short Robust estimator to deal with regression models having both continuous and categorical regressors: a simulation study
title_sort robust estimator to deal with regression models having both continuous and categorical regressors a simulation study
url http://psasir.upm.edu.my/id/eprint/16589/1/16589.pdf
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