Folks, I want to fit a model in which the random effects are 'experiment' and 'block(experiment)'  in NLMIXED. Since NLMIXED does not accept two random statements, it is possible to do it in one. However, the challenge is the nesting. In the Littell 2006 book they describe it briefly, but I am not sure how to apply here. Could anyone please help me with that? There are some parts of the code below that are completely wrong and I am not sure how to fix it; Thanks a lot! Marcio %let nexp = 7214  ; %let nblock = 39; data growth; do exp = 1 to &nexp; err1 = 3*rannor(339205); *No idea what is this; do block = 1 to &nblock; err2 = 2*rannor(0); ADG12M = 970 + err1 + err2 ;  *No idea what is this; output; end; end; end; run; proc nlmixed data=growth start ;                                                                                       title2 'Linear broken line';                                                                                                      bounds .145<R<.245;   array aeffect { 1 };     array beffect {&nblock };   parms L= 970  U=-1000 R=.20 .21 s2e=100 1071 2000 ;                                                                                          z1=(x<R)*(R-x);          mean = L + U *(z1) + expffect{1} + blockeffect{B};   model ADG12M ~ normal(mean, s2e);                                                                                                   random eeff beff ~ Normal([0,0], [expvar, 0, blockvar]) subject=exp   out=blups;                                  predict L + U*(z1) out=ppp; run; ... View more

Would someone help me on How to do an Inverse regression in SAS? I actually need to generate Confidence interval of the response variable to a quadratic polynomial model, Thanks, Marcio ... View more