Getting Started Example 2 for PROC NLMIXED

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/*          S A S   S A M P L E   L I B R A R Y                 */
/*                                                              */
/*    NAME: nlmgs2                                              */
/*   TITLE: Getting Started Example 2 for PROC NLMIXED          */
/* PRODUCT: STAT                                                */
/*  SYSTEM: ALL                                                 */
/*    KEYS: Logistic-normal model                               */
/*          Binomial data                                       */
/*          Multi-center clinical trial                         */
/*   PROCS: NLMIXED                                             */
/*    DATA: Beitler and Landis (1985)                           */
/*                                                              */
/* SUPPORT: Oliver Schabenberger                                */
/*     REF:                                                     */
/*    MISC:                                                     */
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data infection;
  input clinic t x n;
  datalines;
1 1 11 36
1 0 10 37
2 1 16 20
2 0 22 32
3 1 14 19
3 0  7 19
4 1  2 16
4 0  1 17
5 1  6 17
5 0  0 12
6 1  1 11
6 0  0 10
7 1  1  5
7 0  1  9
8 1  4  6
8 0  6  7
;

proc nlmixed data=infection;
   parms beta0=-1 beta1=1 s2u=2;
   eta    = beta0 + beta1*t + u;
   expeta = exp(eta);
   p      = expeta/(1+expeta);
   model x ~ binomial(n,p);
   random u ~ normal(0,s2u) subject=clinic;
   predict eta out=eta;
   estimate '1/beta1' 1/beta1;
run;