Monte Hall question

Monroe Claxton

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Jun 4, 2015
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Say you are a contestant on a game show. You are facing three closed doors. There is a dead possum behind one of the doors, a giant portrait of Tom Crean behind another door, and a 2017 Vespa scooter signed by Cal behind another door. The host asks you to select a door and you pick door number 2.The host opens door number 1 revealing the dead possum. You are then given a choice of staying with your previously selected door number 2 or switching to the other unopened door, door number 3.
Most sensible folks would say it don't make no difference because you have 50/50 chance of getting Tom Crean's portrait. But according to one of the attorneys at Morgan & Morgan, you should switch.
 

UK_Is_Good

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Dec 7, 2005
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You have a 2/3 chance of winning if you switch. The only way you lose is if you pick the prize to begin with (1/3 chance). If you pick any of the other two, you win if you switch.
 
Feb 24, 2009
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You have a 2/3 chance of winning if you switch. The only way you lose is if you pick the prize to begin with (1/3 chance). If you pick any of the other two, you win if you switch.
I believe you have a 50% chance if you switch. You had a 33% chance when you first chose and that carries over if you stay.

But that doesn't change the fact that Larry should be playing in traffic.

EDIT: 66% is the correct answer. Sorry. I still feel the same about Larry, though.
 
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TruBluCatFan

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Dec 21, 2001
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Go watch the movie 21. They discuss the gaming strategy on this exact scenario, well except the prizes are different.
 

IamnotRalph

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In that scenario, I just keep the possum rather than risk the Crean poster.

I think the actual problem is: you pick door one, Monty Hall tells you door #2 is the possum, so you either have the the Crean poster or the Cal scooter. Do you want to keep door one or trade for door 3?

You always trade for the other door. The reason: you have a 1/3 chance of initially choosing the correct door. That means there is 2/3 chance the prize you want is behind one of the other doors. So if Monty takes a guaranteed loser from one of those two doors, the remaining door now has a 2/3 chance of being the winner. By switching, you will win 2/3's of the time over long haul.
 

DSmith21

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You only go on game shows that feature former playmate hosts (like McCarthy & Electra). That is the only way to "win".