Biostatistics and Research Decision Sciences, Merck Research Laboratories, Rahway, NJ, USA 07065.|Target Sciences, GSK, King of Prussia, Philadelphia, PA 27513, USA.|OmicSoft Corporation, Cary, NC 27513, USA.|Target Sciences, GSK, Stevenage, SG1 2NY UK.|Target Sciences, GSK, King of Prussia, Philadelphia, PA 27513, USA.