Thanks to everyone who answered my question. The various reservations about such a test were spot on, and helpful. My own reservations were because, I think, it is not at all clear what the null would be in this case. Are you testing mu = beta_0 (so using the null model with fixed mean) or beta_0 = mu (so using the regression model with potentially variable mean). Alan -- Alan McLean ([EMAIL PROTECTED]) Department of Econometrics and Business Statistics Monash University, Caulfield Campus, Melbourne Tel: +61 03 9903 2102 Fax: +61 03 9903 2007 ================================================================= Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =================================================================