options ls=78;
title "Eigenvalues and Eigenvectors - Wechsler Data";

 /* The first two lines define the name of the data set with the name 'wechsler'
  * and specify the path where the contents of the data set are read from.
  * Since we have a header row, the first observation begins on the 2nd row,
  * and the delimiter option is needed because columns are separated by commas.
  * The input statement is where we provide names for the variables in order 
  * of the columns in the data set. If any were categorical (not the case here), 
  * we would need to put a '$' character after its name.
  */

data wechsler;
  infile "D:\Statistics\STAT 505\data\wechsler.csv" firstobs=2 delimiter=',';
  input id info sim arith pict;
  run;

 /* This prints the specified variable(s) from the data set 'wechsler'. 
  * Since no variables are specified, all are printed.
  */

proc print data=wechsler;
  run;

 /* The princomp procedure calculates the eigenvalues and eigenvectors 
  * for the variables specified in the var statement. The default is 
  * to operate on the correlation matrix of the data, but the 'cov' option 
  * indicates to use the covariance matrix instead.
  */

proc princomp data=wechsler cov;
  var info sim arith pict;
  run;