hidden in view but you can see when you edit an entry

hidden in view but you can see when you edit an entry

hi
when I change the "no of columns displayed", I can see anyway my "effort time" in the view when I make an edit on this entry (it's a number field) thats just what I want to hide !! I need this number field in the form for any user of my group but not for external user they can see only views.
what can I do :?: