/****************************************************************/
/*          S A S   S A M P L E   L I B R A R Y                 */
/*                                                              */
/*    NAME: nlmgs1                                              */
/*   TITLE: Getting Started Example 1 for PROC NLMIXED          */
/* PRODUCT: STAT                                                */
/*  SYSTEM: ALL                                                 */
/*    KEYS: Logistic growth curve with random effects           */
/*          Growth data                                         */
/*          Continuous response                                 */
/*   PROCS: NLMIXED                                             */
/*    DATA: Orange tree data, Draper and Smith (1981)           */
/*                                                              */
/* SUPPORT: Oliver Schabenberger                                */
/*     REF:                                                     */
/*    MISC:                                                     */
/****************************************************************/

data tree;
  input tree day y;
  datalines;
1  118   30
1  484   58
1  664   87
1 1004  115
1 1231  120
1 1372  142
1 1582  145
2  118   33
2  484   69
2  664  111
2 1004  156
2 1231  172
2 1372  203
2 1582  203
3  118   30
3  484   51
3  664   75
3 1004  108
3 1231  115
3 1372  139
3 1582  140
4  118   32
4  484   62
4  664  112
4 1004  167
4 1231  179
4 1372  209
4 1582  214
5  118   30
5  484   49
5  664   81
5 1004  125
5 1231  142
5 1372  174
5 1582  177
;

proc nlmixed data=tree;
   parms b1=190 b2=700 b3=350 s2u=1000 s2e=60;
   num = b1+u1;
   ex  = exp(-(day-b2)/b3);
   den = 1 + ex;
   model y ~ normal(num/den,s2e);
   random u1 ~ normal(0,s2u) subject=tree;
run;