Hi, I am trying to use proc nlmixed on a set of simulated data to check for different models and their AIC/BIC criteria. This attempt below is to model the first one which is: response = y0*exp(-kd*t). Below, I have the simulated data, dropped the parameter kd and then try to fit the nlmixed: data simulated; call streaminit(9); do subject =1 to 100; y0=rand('normal',1,5); k1=rand('normal', 2,2); k2=rand('normal',7,2); kd=rand('normal',2,3); do t = 1 to 10; response=y0*exp(-kd*t); output; end; end; run; data simulated2; set simulated; drop kd; run; proc nlmixed data=simulated2 method=gauss; parms kd=1 delta=0.5 s2=2; pred=y0*exp(-kd*t); model response~normal(pred, pred**(2*delta)*s2); random kd ~ normal(1,2) subject=subject; run; I am getting the following error: NOTE: Execution error for observation 11. There's nothing specific about observation 11 which is the first record for subject 2: Any thoughts/help on this would be much appreciated!! Thank you!
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