The same with hockey. In the die example probability theory application is a simple, unalterable fact, the chance of rolling a 4 on one die is one out of six. In sports it s all really a matter of opinion. That s right, all of the odds that come out of Vegas or anywhere else is just someone s guess as to what the probabilities should be. Most of the time the public is content to accept these odds as being the right odds, but sometimes the odds are so obviously wrong that professional bettors will wager large sums on the dog, sometimes making them the new favorite.
Nobody can possibly know what the true odds are for a sporting event.
The many factors that can change the course of a game are just part of the consideration. How the oddsmaker arrives at his probabilities could be very simple, or very complicated. I seriously doubt that the outcome will differ much. As I write this we are in the middle of the baseball season. Away favorites have won 189 games and lost 185, just about 50-50.