yet another reply to pred vs. DV

From: "Bonate, Peter, Quintiles" <pbonate@qkcm.quintiles.com> Subject: yet another reply to pred vs. DV Date: Tue, 2 Feb 1999 15:38:34 -0600 I think Mats has done a great job of summarizing what must have been a slow morning for most of us. A couple of comments, Lew Sheiner was puzzled over my emphasis on regression relationships. I never meant to imply that someone would want to regress Pred vs. DV or DV vs. Pred and examine the regression parameter estimates. What I was trying to do was show why Mick Looby got the results that he observed and to make the case that at best a regression line should be for visual inspection only. Second, I partially disagree with Mats. Pred will be fixed when the model is certain and the covariates are known with certainty. Since this may not be the case, then pred will be random. Granted it may not be random with mean zero as we traditionally think of random variates but it will have some center of mass which should be pred. PETER L. BONATE, PhD. Clinical Pharmacokinetics Quintiles POB 9627 (F4-M3112) Kansas City, MO 64134 phone: 816-966-3723 fax: 816-966-6999