Monty Hall Dilemma - 3 Doors Game

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Overview

This is a simulation of the Monty Hall Dilemma. The game starts off with three closed doors. Only one of them hides a surprise, while the others are empty. After you choose one of the doors, one of the other doors will be revealed as empty. Your next choice is between your first pick and the other remaining closed door. Which one will you choose? Which odds are better to pick the surprise?

To begin playing, click on the link above. When it loads in the new window, press the start button. At that point, the surprise will be randomly hidden. When the game is over, press start to play again. Your results will be summarized, so you can track the probabilities of either staying or switching.

There is also a set of "Cheat" text boxes at the bottom of the window. Only check off "Cheat" if you want the location of the surprise to be revealed in the text boxes. Of course, if you're cheating, the probability results will not be accurate. It's only there to prove that the game isn't fooling you and moving around the surprise in the middle of the game.

Background Information

The Monty Hall Dilemma has also been called the "Let's Make a Deal" problem and other similar names. The topic was discussed in Marilyn vos Savant's Parade magazine column, "Ask Marilyn", in 1991. A lot of interest on the Internet has developed as a result. There are sites explaining the problem and its mathematical solution. There are sites that have playable versions of the problem, and some that simulate multiple attempts. Here are some links to various sites:

Monty Hall Dilemma at cut-the-knot.com - Has an explanation of the problem and a playable game.
The Three Card Monty Hall Dilemma - Includes a playable game, plus the ability to simulate multiple attempts at once.