The Monty Hall Problem


Welcome to the probability problem that has vexed many a person over many a year. Rumours about this problem have flown far and wide, the most egregious being that the wrong answer was once published in a journal. When the woman with the highest known IQ (at the time) wrote in with a correction, her correction was refused because it is quite counter-intuitive. I, myself, have seen professors of mathematics run computer simulations because they did not believe the theoretical result.

How to play

The question is simple: there are three doors, with the prize of your dreams behind one of them (use your imagination). You select one door, and the host decides he's going to be nice to you; he shows you which of the other doors definitely does not contain the prize. Your task now is to decide: do you stick with your choice, or do you change your mind and opt for the one remaining closed door.
This java applet was originally developed for use by the CS 273 class at the University of Illinois.

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