[1] Calif State Univ Long Beach, Dept Math & Stat, Long Beach, CA 90840 USA
[2] Univ Calif Irvine, Dept Stat, Irvine, CA USA
[3] US FDA, Div Bioinformat & Biostat, Natl Ctr Toxicol Res, Jefferson, AR USA
[4] China Med Univ, Ctr Biostat, Sch Publ Hlth, Taichung, Taiwan
[5] Univ Arkansas Med Sci, Dept Biostat, Little Rock, AR 72205 USA