Hi ti all, I am using psm() function of the Design package with dist=' weibull '. I think that Design uses the following weibull R*L*(R*L)^(R-1). Using psm() with dist= "weibull" I get estimates of Log(scale) and intercept . Does anybody knows the relation between R, L and intercept and scale parameters? I think that R=scale but I am not sure .In addition wich is the accelerator factor ? Best regards D.Lalountas University of Patras __________________________________________________ [[alternative HTML version deleted]]