Documentation Example 3 for Introduction to SEM
/****************************************************************/
/* S A S S A M P L E L I B R A R Y */
/* */
/* NAME: ICALEX2 */
/* TITLE: Documentation Example 3 for Introduction to SEM */
/* PRODUCT: STAT */
/* SYSTEM: ALL */
/* KEYS: measurement error model, spleen data */
/* PROCS: CALIS */
/* DATA: */
/* */
/* SUPPORT: yiyung UPDATE: September 14, 2009 */
/* REF: Introduction to SEM, Example 3 */
/* MISC: */
/****************************************************************/
data spleen;
input rosette nucleate;
sqrtrose=sqrt(rosette);
sqrtnucl=sqrt(nucleate);
datalines;
4 62
5 87
5 117
6 142
8 212
9 120
12 254
13 179
15 125
19 182
28 301
51 357
;
proc calis data=spleen;
lineqs factrose = beta * factnucl + disturb,
sqrtrose = factrose + err_rose,
sqrtnucl = factnucl + err_nucl;
variance
factnucl = v_factnucl,
disturb = v_disturb,
err_rose = v_rose,
err_nucl = v_nucl;
run;
proc calis data=spleen residual;
lineqs factrose = beta * factnucl + disturb,
sqrtrose = factrose + err_rose,
sqrtnucl = factnucl + err_nucl;
variance
factnucl = v_factnucl,
disturb = v_disturb,
err_rose = 0.25,
err_nucl = 0.25;
run;
proc calis data=spleen residual;
lineqs factrose = beta * factnucl + disturb,
sqrtrose = factrose + err_rose,
sqrtnucl = factnucl + err_nucl;
variance
factnucl = v_factnucl,
disturb = 0.,
err_rose = 0.25,
err_nucl = 0.25;
run;
proc calis data=spleen;
path
sqrtrose <=== factrose = 1.0,
sqrtnucl <=== factnucl = 1.0,
factrose <=== factnucl ;
pvar
sqrtrose = 0.25, /* error variance for sqrtrose */
sqrtnucl = 0.25, /* error variance for sqrtnucl */
factrose, /* disturbance/error variance for factrose */
factnucl; /* variance of factnucl */
run;