1. David A. van Dyk is Professor, Department of Statistics, University of California Irvine, Irvine, CA 92697 . Taeyoung Park is Assistant Professor, Department of Statistics, University of Pittsburgh, Pittsburgh, PA 15260 . This project was supported in part by National Science Foundation grant DMS-01-04129, DMS-04-38240, and DMS-04-06085 and by National Aeronautic and Space Administration contracts NAS8-39073 and NAS8-03060 (CXC).