1. Willa W. Chen is Assistant Professor of Statistics, Texas A&M University, College Station, TX 77843 . Clifford M. Hurvich is Professor of Statistics and Yi Lu is a Ph.D Student , New York University, New York, NY 10012. The research of Chen was supported by National Science Foundation grant DMS-03-06726. The authors thank the editor, the associate editor for their helpful comments that greatly improved this manuscript.