Monty Hall

Mike Rudolph (nitefyre@netcom.com)
Mon, 04 Dec 1995 00:02:17 -0800


Wow, this problem is a fossil for the chat room. I agree with Karen (since she basically
emphasized what I posted way back in the day)... the situation can be basically broken down
into two stages. However, the first stage can basically be ignored, since all the host is
doing is eliminating one option. It may not sound right, but to me this is what is actually
happening:

-=- STAGE ONE -=-

You have a 1/3 chance of picking the door with the car. If you pick a goat or a car, the
game is not over, you will proceed to stage two regardless and the host will expose a door
you didn't choose that contains a goat.

-=- STAGE TWO -=-

Setup: One door with a goat, one door with a car.

The host basically is asking you to pick one of two doors. If he exposed Door 3 as a goat,
he wants you to pick either Door 1 or Door 2. He phrases it as "do you want to change the
door you picked?" but he is really just asking you to pick one of the two doors. So
irregardless of which door you choose, your chances are 50%-50% because there are two doors,
one that has a car, one that has a goat. The Stage One is more of a distraction that
actually having to do with your probability of winning.

This all assumes the host is totally neutral, which isn't always the case. If he was biased
one way or the other, you have no idea which door to pick, because the host can be either
trying to "entice" you to the door you didn't pick or can be using reverse psychology to
keep you with the door you did pick. I guess I would watch the show for a month beforehand
and see what the general pattern of what the host does is, to see if he is being impartial
or not, and make a judgement that way.

- Mike
Good luck on them essays, they're do tomorrow!



Back to the Chatroom Homepage...

Back to the Stats 154A Homepage...

Back to the listings...

Send a message...


This archive was generated by hypermail 1.02.