title:
  Data from table 2.1, page 20.
  Input 3.2 page 36.
  Figure 3.1 page 36.
  Output page 37 and table 3.4 and 3.5.
  ** NOTE ** Output does not match because 
    time is coded 0 1 2 (a traditional coding)
data:  
  file is ch2.dat;
  format is free;
  type is correlation means stdeviations;
  nobservations = 343;
variable:  
  names are y1 y2 y3; 
  usevar =  y1-y3;
analysis:
  type = general meanstructure;          
model: 
  int linear quad | y1@0 y2@1 y3@2 ;
  [y1-y3@0];
  y1-y3@0;