There are a lot of variables. Screen brightness play a part in battery drain, but it also depends on what you do. I average 6-7 hrs. with brightness at about 50% but all I do is browse the web, photo editing, digital scrapbooking, & school work (word/PPT/excel/onenote).
When you say 6-7 hours, is that with intermittent use? Do you get 6-7 hours of solid use (not leaving it in standby) whilst web browsing, photo editing etc?