1. Baojiang Chen is Acting Instructor, Department of Biostatistics, University of Washington, Seattle, WA 98195. Grace Y. Yi is Associate Professor and Richard J. Cook is Professor, Department of Statistics and Actuarial Science, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1. The authors are grateful to Professor Roy Cameron for permission to use the data from the WSPP. The authors thank the editor, the associate editor, and the referee for their helpful comments....