When creating new column formats in the proc format step, why do you sometimes need a dollar sign before the format name and sometimes you don't? In this example I cam trying to make two new custom column formats - genftm and hrange.
proc format;
value $genfmt 'F'='Female'
'M'='Male';
value hrange 50-57='Below Average'
58-60='Average'
61-70='Above Average';
run;