I would say that if they were exactly the same odds, they will have exactly the same chance.
The horse has 7 others running, might miss the jump, might break down, could have bad luck in running or find a smokey that's fitter / or an up and comer.
A soccer match can also be unpredictable, there might be an injury to a star player or two players get red carded, or they just fumble the whole thing. Seen heaps of this happen.
When you consider gallops, trots, uk jumpers, teams, and individual players, the bookies adjust the odds to the true chance plus vig.
Personally, I think a $1.10 chance is the same everywhere.
The stats would seem to indicate so, except "in running"
