/*-----------------------------------------------------------------
            S A S   S A M P L E   L I B R A R Y                   
                                                                  
      NAME: ICALEX1                                               
     TITLE: Documentation Example 2 for Introduction to SEM       
   PRODUCT: STAT                                                  
    SYSTEM: ALL                                                   
      KEYS: measurement error model, corn data                    
     PROCS: CALIS                                                 
      DATA:                                                       
                                                                  
   SUPPORT: yiyung                UPDATE: September 9, 2009       
       REF: Introduction to SEM, Example 2                        
      MISC:                                                       
-----------------------------------------------------------------*/

data corn(type=cov);
   input _type_ $ _name_ $ y x;
   datalines;
cov    y    87.6727    .
cov    x    104.8818   304.8545
mean   .    97.4545    70.6364
n      .    11         11
;

proc calis;
   lineqs
      Y  = alpha * Intercept + beta * Fx + Ey,
      X  =     0 * Intercept +    1 * Fx + Ex;
   variance
      Ex = 57;
   mean
      Fx;
run;

proc calis;
   lineqs
      Y  = alpha * Intercept + beta * Fx + Ey,
      X  =     0 * Intercept +    1 * Fx + Ex;
   variance
      Ex = 0;
   mean
      Fx;
run;

proc calis data=corn;
   lineqs
      Fy  = alpha * Intercept + beta * Fx + DFy,
      Y   = 0     * Intercept + 1.   * Fy + Ey,
      X   = 0     * Intercept + 1.   * Fx + Ex;
   variance
      Ex  = 57.,
      Dfy = 0.;
   mean
      Fx;
run;