Outlier Detection Methods in Multivariate Regression Models BY JIAQIONG XU Center for American Indian Health Research, College of Public Health, University of Oklahoma Health Sciences Center, P.O.Box 26901, Rm CHB100, Oklahoma City, OK 73190 U.S.A. susan-xu@ouhsc.edu BOVAS ABRAHAM Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, ON N2L 3G1 Canada. babraham@uwaterloo.ca AND STEFAN H. STEINER Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, ON N2L 3G1 Canada. shsteine@uwaterloo.ca Corresponding author: Bovas Abraham , Department of Statistics and Actu- arial Science, University of Waterloo, Waterloo, ON N2L 3G1 Canada. E-mail: babraham@uwaterloo.ca 1