Suppose you’re on a game show, and you’re given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what’s behind the doors, opens another door, say No. 3, which has a goat. He then says to you, “Do you want to pick door No. 2?” Is it to your advantage to switch your choice?

Posted 14 years ago

yes.

Posted 14 years ago

More exact phrasing:

Suppose you’re on a game show and you’re given the choice of three doors. Behind one door is a car; behind the others, goats [that is, booby prizes]. The car and the goats were placed randomly behind the doors before the show. The rules of the game show are as follows: After you have chosen a door, the door remains closed for the time being. The game show host, Monty Hall, who knows what is behind the doors, now has to open one of the two remaining doors, and the door he opens must have a goat behind it. If both remaining doors have goats behind them, he chooses one randomly. After Monty Hall opens a door with a goat, he will ask you to decide whether you want to stay with your first choice or to switch to the last remaining door. Imagine that you chose Door 1 and the host opens Door 3, which has a goat. He then asks you “Do you want to switch to Door Number 2?” Is it to your advantage to change your choice?

Posted 14 years ago

still yes.

Posted 14 years ago

Yes. You have a 1/2 chance of getting a car if you switch, but only a 1/3 if you stay put.

Posted 14 years ago

doesn’t matter.

Posted 14 years ago

No.
It’s now 50/50 whichever door you go for.

Posted 14 years ago

Wesley Snipes?

Posted 14 years ago

but it was 1 in 3 when you made you first choice.

Posted 14 years ago

You should always switch as you get a 66% chance of winning if you switch…

😀

Didn’t I post a Monty Hall thread a couple of hours ago though?

Posted 14 years ago

Monty Hall Question

Surely this one has been done already?

You should switch as the probability is now 2/3 for the other door. End of.

Posted 14 years ago

Didn’t I post a Monty Hall thread a couple of hours ago though?

I didn’t see it. If I switch to that thread do I have a better chance at laughing at people?

Posted 14 years ago

miketually… nope.. I think I only got 2 replies, and one of those was from me!

Posted 14 years ago

Does it matter in what order you got the replies? 🙂

Posted 14 years ago

Yes, or at least 66% of the time it does… 😀

Posted 14 years ago

miketually – have you been reading The curious incident of the dog in the night time by any chance??

Posted 14 years ago

Switch every time, as waswas says. When you chose door 1 you had a 33% chance of being correct. Now you have a choice of 2, by switching you have a 50% chance of being correct.

Besides, if you end up with the goat you can’t drive around but it’s regular sex at least.

Posted 14 years ago

AAAAHhhh!!! Just open the frickin open the door!!! 😈

Posted 14 years ago

So, what about deal or no deal, when they get offered the swap at the end? there were 22 boxes, he’s stuck with it all the way until there is just his box and one other. would it be better to swap?

Posted 14 years ago

Can I just take the goat behind 3? My lawn’s a bit overgrown and I’m happy with my motor.

Posted 14 years ago

pk-ripper.. so close… you got the 33% bit, but once you take away the other door, the only door remaining must have a probability of 66%.

Posted 14 years ago

but I was right about the regular sex though.

Posted 14 years ago

tomzo – Member

So, what about deal or no deal, when they get offered the swap at the end? there were 22 boxes, he’s stuck with it all the way until there is just his box and one other. would it be better to swap?

It’s a nice idea, but one that would only work if there were 21 boxes with (let’s say) £1 in them and 1 box with £250,000. In which case if you were left with two boxes at the end and one was still the £250k box then you’d be an idiot not to switch as you’d have a 95% probability of winning the big prize by switching.

Posted 14 years ago