Usually! Sometimes there are shockers, but most of the time they're correct.
The lower the number, the more likely for it to happen.
Let's just say New York had a 10-1 odds of winning Big Brother. If you bet $1 on her, you would win $10, since her odds were 10-1. The higher the odds, the least likely it is going to happen.
It's usually a good indicator on who is doing well.