The role of probability in solving the Monty Hall problem

[Jenny A]

There are no patterns to consider. One door always has the prize, and the others don't. Choose one door and you have a one third chance of winning. Choose two doors and you have a two thirds chance of winning. After Monty's reveal switching gives you effectively two rather than one doors. Staying with the first door leaves you with a one third chance.


EDIT: Look around it this way. Suppose you had the choice of choosing one door or choosing two doors initially with the understanding that Monty would show you a goat behind one of the two doors you choose and you'd get the remaining door of your two door choice. That's what's actually happening if you switch.