proc format;
  value school
      5-11="Elementary" 12-14="Junior High" 15-19="High School";
run;
proc sort data=sashelp.class out=ByAge(keep=Name Age Height Weight);
  by Age Height;
run;
data YoungestBySchoolGroup;
  set ByAge;
  by Age notsorted groupformat;
  format Age school.;
  if first.Age;
run;
proc print data=YoungestBySchoolGroup;
  title1 "Youngest Student in each School Group";
run;