/* aug25.ex4c                       */
 /* ********** corrected version *****/
 /* *** but still a subtle problem ***/
 /*                                  */
 /* read Amy Nail's test file        */
 /*   compute running means and let  */
 /*   proc means compute daily max   */
 /*                                  */
 /* make pointer to directory        */
 /*                                  */
  libname amy '.' ;                  * already at the directory ;
 /*                                  */
 /* two step process                 */
 /*  make 8-hour rolling ave's       */
 /*  then means to get max           */
  data a ;
    drop co ald2 hourlst ;
    format datelst date9. ;          * careful here ;
    set amy.smoke36_forjm ;
    cor8ave = (co + lag(co) + lag2(co) + lag3(co) + lag4(co)
                 + lag5(co) + lag6(co) + lag7(co))/8 ;
    alr8ave = (ald2 + lag(ald2) + lag2(ald2) + lag3(ald2) + lag4(ald2)
                 + lag5(ald2) + lag6(ald2) + lag7(ald2))/8 ;
    if( hourlst gt 6 ) then output ; * only after 7 ;
   run ;
 /*                                  */
 /* proc means for each day's max    */
  proc means data=a max noprint nway ;* nway !!!! ;
    class grid36id datelst ; 
    var cor8ave alr8ave ;
    output out=b max= ;
   run ;
 /*                                  */
 /* print the top                    */
  proc print data=b (obs=20) ;
    title 'top of dataset' ;
   run ;
 /*                                  */
 /* print the bottom                */
  proc print data=b (firstobs=10900) ;
    title 'bottom of dataset' ;
   run ;