************************************************************************ * FIT OF A LOGNORMAL FUNCTION WITH AR ERRORS TO AN UNIMODAL CURVE * * BY USING NONLINEAR GLS AND * * A LINEAR WLS APPROACH FOR OBTAINING STARTING VALUES * ************************************************************************; *------------------------------------------------------------------* | QUESTIONS ? | | | | ---> Dr. Ralf BENDER Phone: +49 221 35685-451 | | Fax: +49 221 35685-891 | | E-Mail: Ralf@rbsd.de | *------------------------------------------------------------------*; * NOTE: The data set 'CURVE' must contain at least 2 Variables: *; * 1) t for the time points and *; * 2) Y for the curve points used. *; *---------------------------------------------------------------------* | Initial Estimation | *---------------------------------------------------------------------*; *------------------------*Log-Transformation*-------------------------*; data lin; set curve; if Y<=0.0001 then Y=0.0001; G = log(Y); X1 = log(t); X2 = log(t)**2; w = Y; if 0