NationStates Jolt Archive

You're on a game show, and you have reached the final round. There are three doors, behind one of which is the grand prize. The other two have gag prizes, or no prizes, doesn't really matter - point is, they have nothing you'd want.

You pick a door, at which point the host of the game show opens one of the remaining doors that you didn't pick, to reveal it's not the correct door. The host then offers you the chance to change doors, or stick with the one you've chosen.

And now for the big question: What will the odds of winning be if you change doors?

Think very carefully, it's not as simple as it sounds. ;)

MATH! EVIL!
But lets see if I still know how to do this...

It was one of three...wait, wouldn't it be just 1/2???

Wait...no...i haven't a clue.

edited to protect the innocent.

MATH! EVIL!
But lets see if I still know how to do this...

It was one of three...wait, wouldn't it be just 1/2???

Wait...no...i haven't a clue.

All logic and common sense I can muster says yes, but statistics says no. ^_^; To this day I still don't fully understand why it isn't 50%... but it isn't.

The answer is counter-intuitive: changing doors will be better than if you stick with the one you originally chose. Hang on while I get a pen to work it out.
Hmm, I've heard the exact opposite.

to protect the innocent....

You didn't see that.

[taps nose]

I thought I'd stump people for a while at least... o.o;
I'll edit my answer out, if you edit your quote, ok?

That would be much appreciated. ^_^;

i think the answer would still be 33% or 1 out of 3 because the fact that he opened a door you now couldnt pick doesnt change the individual odds of the prize being behind that door... i may be way off on this but pleas telegram my nation with the answer, we want to know

I know it's not 50%, I just don't know why :confused:

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Check here if you're confused (http://mathforum.org/dr.math/faq/faq.monty.hall.html).

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I'm somewhat disappointed that nobody else has got it yet.

I think you said it best in calling it counterintuitive. It really requires you to think outside the proverbial box.

edit: erased my answer as it was the correct one. wasn't that hard imo. and if you was fast enough you could see that I was right. ;)

I think you said it best in calling it counterintuitive.

A word much beloved of ex-philosophy students everywhere.