[Anonymous]

Behind one lies a car, behind the other two, goats! You choose a door and the host opens one of the two doors you did NOT choose to reveal a goat. Now he says, “Behind one door is a goat, behind the other is a car…would you like to switch?”. Do you switch? Why or Why Not? If applicable, what are your probabilities of winning before and after switching, respectively?

Yes, this is the Monty Hall Paradox for all you smarty-pants’ out there. I think it’s an interesting scenario and I like to see what people would choose.

[oneFREAKINGpoint]

You always switch 🙂

[Anonymous]

I won't say whether or not you are correct until a few more people have had the chance to answer, but don't forget to provide your reasoning (i.e., your probabilities before and after switching, etc.). Thanks for your answer! 🙂

[misanthrope87]

You're supposed to switch. The first time your probability is 1/3, 2nd time is 1/2?

B 2/12 87
A 11/11 90
R 8/11 86
F 5/12 88

[Anonymous]

I'm going to switch.

[Anonymous]

I would stick with the same door. I'd feel better if I stayed with the same door and got the goat than if I switched to the other door and got a goat.

[Anonymous]

Back to the game! Yes, you switch! It's a 1/3 chance at initial door selection and a 2/3 chance if you switch. It's easier to see why if you expand the number of doors. Let's say you have 1,000 doors…behind 1 there is a car, behind 999 there are goats. You select a door and the host opens 998 other doors that have goats behind them. When you initially selected, your chances of winning were 1/1000, but if you switch, they're 999/1000! I remember hearing about this paradox in school and thought it was pretty cool so I thought I'd share it 🙂

[mla1169]

I'm way too stubborn to switch. Besides will a car mow my lawn?

FAR- 77
AUD -49, 71, 84
REG -56,75!
BEC -75

Massachusetts CPA (non reporting) since 3/12.

[Minimorty]

True story – I won a car three years ago in Las Vegas on The Price is Right Las Vegas version. lol. It was a Mazda 3. I took the cash in liu of the car. lol.

[mla1169]

I wanna go to Vegas lol! Pretty stoked just to sneak away to Foxwoods for a day. Pa-the tic huh!

FAR- 77
AUD -49, 71, 84
REG -56,75!
BEC -75

Massachusetts CPA (non reporting) since 3/12.

[Anonymous]

While this thread is not specifically accounting or CPA exam related, it does make you think about numbers and their relationships, which is what we all do every day. Brain teasers like this help to keep you sharp and make you think. Certain comments were deleted, most because they were not “value added” and a couple because they didn't make any sense after I deleted the others. Please, no drama. I am asking as nicely as I know how. Please, please, no drama!

[Minimorty]

We are planning an A71 Vegas trip. I think it's in the Swangin and Bangin thread. 😉

[herbert7890]

I'm not getting this. First selection I have a 33% Chance (1/3) thats ok, But no matter what selection I make or If I decide to switch after the initial selection,my chances CANT change from 50%, as there is only 2 choices. You have to eliminate the goat he showed up from the sample, as you already know that's removed. Hence, my odds cant increase to 2/3 as there is only 2 scenarios left.

FAR 88 - BEC 86 - AUD 90 - REG 85

[Witchkizzle]

@herbert

It has to do with the percentage chance of picking the goat the first time. You had to choose between two goats and one car, so there was a 66% chance you picked the goat first and SHOULD swap for the car. While you only had a 33% chance of picking the car first and then swapping for the remaining goat.

It makes you want to think about it as two separate and non-related choices, but the second choice always relies on the first choice.

Texas CPA
Licensed 03/12

[RedStorm45]

This is from the movie 21 (or well, it was made popular in the movie 21) or the book that the movie was based off – Bringing Down the House.

Yes, you switch. Every door has a 2/3 chance of being a goat. By eliminating 1 of the doors, you increase your odds that the other door remaining is in fact the car.

Starting all over.

FAR - 11/27/13
AUD - 1/4/14

[herbert7890]

Ok got it now ; )

FAR 88 - BEC 86 - AUD 90 - REG 85

[Author]

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