Documentation Example 4 for PROC NLIN
/****************************************************************/
/* S A S S A M P L E L I B R A R Y */
/* */
/* NAME: nlinex4 */
/* TITLE: Documentation Example 4 for PROC NLIN */
/* Affecting Curvature Through Parameterization */
/* PRODUCT: STAT */
/* SYSTEM: ALL */
/* KEYS: Reparameterization */
/* Log-logistic model */
/* Smoothness condition */
/* PROCS: NLIN, SGPLOT */
/* DATA: */
/* */
/* SUPPORT: Oliver Schabenberger */
/* REF: */
/* MISC: */
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data logistic;
input dose y;
logdose = log(dose);
datalines;
0.009 106.56
0.035 94.12
0.07 89.76
0.15 60.21
0.20 39.95
0.28 21.88
0.50 7.46
;
proc sgplot data=logistic;
scatter y=y x=dose;
xaxis type=log logstyle=linear;
run;
proc nlin data=logistic bias hougaard nlinmeasures;
parameters alpha=100 beta=3 gamma=300;
delta = 0;
Switch = 1/(1+gamma*exp(beta*log(dose)));
model y = delta + (alpha - delta)*Switch;
run;
proc nlin data=logistic bias hougaard;
parameters alpha=100 beta=3 LD50=0.15;
delta = 0;
Switch = 1/(1+exp(beta*log(dose/LD50)));
model y = delta + (alpha - delta)*Switch;
output out=nlinout pred=p lcl=lcl ucl=ucl;
run;
proc nlin data=logistic bias hougaard nlinmeasures;
parameters alpha=100 mustar=20 LD50=0.15;
delta = 0;
xstar = 0.3;
beta = log((alpha - mustar)/(mustar - delta)) / log(xstar/LD50);
Switch = 1/(1+exp(beta*log(dose/LD50)));
model y = delta + (alpha - delta)*Switch;
output out=nlinout pred=p lcl=lcl ucl=ucl;
run;