PROC Means data= <dataset> ;
  VAR <psychometric-var> ;
  OUTPUT Out=<NEW_Dataset> std= <var_SD> ;
RUN;

DATA _null_;
  SET <NEW_Dataset>; 
  CALL Symput ( "sigma",<var_SD> );
RUN;
*** Using newly created macro-variable in a datastep ***;
DATA test2; 
   SET <dataset>;
   <Norm-psychometric-var> = ( <psychometric-var> )/( &sigma );
RUN;