If you can figure this out...you are a genius

[anonymous]

[tuna4lyfe]

(have not read the whole thread)

They did this on an episode of mythbusters, conclusion:

starting % per door: 33,33,33

u pick one.

whats left is: 66,33

cant explain this with any more detail since I saw that episode like a year back... think its called something with gameshow.

people saying its 50/50 when there is two doors left are wrong. that was my first conclusion also, but in this episode of mythbusters they made it very clear why that is not the case.

Edit: found YT video, also did not notice that the thread is from 2006=))



04:20 and forward

[dtbrehm]

Wait, why is this thread so big?

Edit: nevermind it's from 2006..

[matt01621]

Try this one out, and be sure to explain your answer because that is the only way it matters:

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 number 1, and the host, who knows what's behind the doors, opens another door, say number 3, which has a goat. He says to you, "Do you want to pick door number 2?" Is it to your advantage to switch your choice of doors? Why or why not?


They say only 5% of the population will come to the correct reasoning of this problem. Can you?

You switch doors


http://en.wikipedia.org/wiki/Monty_Hall_problem

/thread

[MacIsaac]

Keep your choice and use the goat to sell goats milk win win

[zzzboy]

OFFICIAL EXPLANATION THAT ANYONE CAN UNDERSTAND.

if i have a pile of 100 cards and only ONE ace in that pile, and i draw a random card, i now have two piles: one card pile, and 99 card pile.

so, the probability the ace is in the 99 card pile is 99%. NOW, if i ONLY TAKE AWAY 98 WRONG CARDS (ie NOT ACE) from the 99 pile until i have two piles of 1, THEN THE PROBABILITY THAT THE CARD IS IN THE ORIGINAL 99 PILE (now 1 card) IS STILL 99% SINCE I ONLY REMOVED WRONG CARDS. THUS, 99% CHANCE OF ME WINNING BY SWITCHING.

that is the crux of the problem. the host will NEVER reveal a car just like you won't remove an ace from the 99 pile. thus, there is 2/3 chance that the car is in the other 2 doors you didn't pick. host reveals a wrong option from those 2 doors...STILL 2/3 ON THE OTHER DOOR SINCE IT WAS LUMPED WITH THE OTHER DOOR AND ONLY WRONG OPTION REVEALED.

if the host or you COULD remove a RIGHT option (car or card), then of course there is no advantage to switching.

[frgz88]

loling at replies saying "simple math problem", then reasoning that once a goat is revealed, you have a 50% chance to win by switching.

[MaximusPlatypus]

switch

at first you have 1 in 3 chance (33%) of getting it

after switching you now have 1 in 2 chance (50%) of getting it
if you do not, you are still with original 33% chance

And a 13% chance of balls touching lulz. Strong math

[FawkinJuicyBrah]

Wut if u want the goat?

[swoleclitorous]

Everysingle one of you in this thread apart from about two people are fuking morons.


You do realize the whole reason everyone thinks its better to switch is because of some dumb bitch called Vos Savant, and we all know bitches cant do math.

Their is absolutely no scientific foundation to this whatsoever so fuk this illogical answer, fuk everyone in this thread, and fuk that bitch Vos Savant.



You are all wrong

[Lupes Return]

Everysingle one of you in this thread apart from about two people are fuking morons.


You do realize the whole reason everyone thinks its better to switch is because of some dumb bitch called Vos Savant, and we all know bitches cant do math.

Their is absolutely no scientific foundation to this whatsoever so fuk this illogical answer, fuk everyone in this thread, and fuk that bitch Vos Savant.



You are all wrong

think if there were 1000 doors originally, one with a car and the rest goats. You pick, and then the host eliminated 998 wrong doors and asks if you would like to switch. OF COURSE YOU SHOULD! THE CHANCE YOU PICKED RIGHT THE FIRST TIME IS 1/1000!

[swoleclitorous]

think if there were 1000 doors originally, one with a car and the rest goats. You pick, and then the host eliminated 998 wrong doors and asks if you would like to switch. OF COURSE YOU SHOULD! THE CHANCE YOU PICKED RIGHT THE FIRST TIME IS 1/1000!

NO

It dosent matter when the goat has been revealed, revealing the goat simply lets the player know that he has a 1/2 chance.

The goat was in the box and is still in the box, the reveal does not change anything WHATSOEVER regarding probobilitys.

Think about it, just because the player knows there is a goat in the box, does that change the statistics if nothing has actually physically changed about the situation?

The goat was in the box and is still in the box, the players knowledge of this does not play any role whatsoever.

[Archangel_Lost]

I was actually reading about this today. I heard it explained very plainly with much more sense than the problem itself presents, but I still don't understand where that logic comes from. The easiest explanation I heard was "all the other problems except the right one and the one you picked were eliminated", which still doesn't take into account if the one you picked is right.. I mean, luck doesn't really factor into statistics. All I can think of is that if I picked the right one, then choosing one other random one would just be that... random..

[swoleclitorous]

I was actually reading about this today. I heard it explained very plainly with much more sense than the problem itself presents, but I still don't understand where that logic comes from. The easiest explanation I heard was "all the other problems except the right one and the one you picked were eliminated", which still doesn't take into account if the one you picked is right.. I mean, luck doesn't really factor into statistics. All I can think of is that if I picked the right one, then choosing one other random one would just be that... random..

Well i didnt quite understand what you just wrote, but the whole logic to the switch is flawed.

People seem to think that its a 1 in 3 chance if he stays put because he originally picked box 1 out of 3 options.
The host knows box 3 is a goat and there is an actual goat in box 3, it dosent matter whether the player knows that or not. When he picked box number 1 under the impression he had 3 options he still has a 1/2 chance, since box 3 is still a goat even though it hasent been revealed.

He has a 50/50 chance either way

[Deezenutz]

Why are people still posting ITT? Does no one remember this being in the movie 21? Jesus Christ.

[BigBlobby]

You have a 66% chance of winning if you switch doors, 33% if you stay.

66+33=99....

are you serious?

[AJ010]

Well i didnt quite understand what you just wrote, but the whole logic to the switch is flawed.

People seem to think that its a 1 in 3 chance if he stays put because he originally picked box 1 out of 3 options.
The host knows box 3 is a goat and there is an actual goat in box 3, it dosent matter whether the player knows that or not. When he picked box number 1 under the impression he had 3 options he still has a 1/2 chance, since box 3 is still a goat even though it hasent been revealed.

He has a 50/50 chance either way

3 Doors ( 2 goats, 1 car)
Assume the placement of goats and car is random (i.e there is no way to to know where the goats/car are likely to be placed)

Question 1) What is the probability you pick the goat on your first pick?
Answer 1) The probability is 2/3 (duh???)

Now the host removes a door(goat) for you. So all that remains is a car and a goat.

Mini-Question: Do you have a goat, or a car?
Answer Mini-Question: You don't know for sure, but what you do know is the odds you have a goat is 2/3.

Question 2) Given that you originally picked a goat, what is the probability that switching will get you a car?
Answer 2) 100%

Note: 2/3 * 100% = 2/3

Question 3) Given that you originally picked a car, what is the probability that switching will get you a car?
Answer 3) 0%

Note: 1/3 * 0% = 0

Therefore, the probability of getting a car by switching is 2/3


Simulate this via a computer program if you don't believe us. 2/3 of the time, those that switch will win the car.

[fishpat86]

EDIT: I derped

[rusrs]

Try this one out, and be sure to explain your answer because that is the only way it matters:

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 number 1, and the host, who knows what's behind the doors, opens another door, say number 3, which has a goat. He says to you, "Do you want to pick door number 2?" Is it to your advantage to switch your choice of doors? Why or why not?


They say only 5% of the population will come to the correct reasoning of this problem. Can you?

Wasn't this in the movie 21 or some ****?

[lynch0617]

OP has been watching 21 I see. Also, stick with 1

[fishpat86]

OFFICIAL EXPLANATION THAT ANYONE CAN UNDERSTAND.

if i have a pile of 100 cards and only ONE ace in that pile, and i draw a random card, i now have two piles: one card pile, and 99 card pile.

so, the probability the ace is in the 99 card pile is 99%. NOW, if i ONLY TAKE AWAY 98 WRONG CARDS (ie NOT ACE) from the 99 pile until i have two piles of 1, THEN THE PROBABILITY THAT THE CARD IS IN THE ORIGINAL 99 PILE (now 1 card) IS STILL 99% SINCE I ONLY REMOVED WRONG CARDS. THUS, 99% CHANCE OF ME WINNING BY SWITCHING.

that is the crux of the problem. the host will NEVER reveal a car just like you won't remove an ace from the 99 pile. thus, there is 2/3 chance that the car is in the other 2 doors you didn't pick. host reveals a wrong option from those 2 doors...STILL 2/3 ON THE OTHER DOOR SINCE IT WAS LUMPED WITH THE OTHER DOOR AND ONLY WRONG OPTION REVEALED.

if the host or you COULD remove a RIGHT option (car or card), then of course there is no advantage to switching.

Makes perfect sense.

[swoleclitorous]

3 Doors ( 2 goats, 1 car)
Assume the placement of goats and car is random (i.e there is no way to to know where the goats/car are likely to be placed)

Question 1) What is the probability you pick the goat?
Answer 1) The probability is 2/3

Question 2) Given that you originally picked a goat, what is the probability that switching will get you a car?
Answer 2) 100%

Note: 2/3 * 100% = 2/3

Question 3) Given that you originally picked a car, what is the probability that switching will get you a car?
Answer 3) 0%

Note: 1/3 * 0% = 0

Therefore, the probability of getting a car by switching is 2/3


Simulate this via a computer program if you don't believe us. 2/3 of the time, those that switch will win the car.

Yes the placement is entirely random, but given our situation where the host reveals that box 3 is a goat, and our player picked box 1 it is 50/50.
When our player picked box 1 the goat is still in box 3, do you think that just because the player cant see the goat it makes it 1/3?? No the goat didnt just magically apear when the host revealed box 3. The goat has been there all along, so given that the player picks either box 1 or box 2 from the start he has a 50/50 percent chance regardless.

[NOVA888]

Odds aside, it's this in which I'll make my decision...

the host, who knows what's behind the doors, opens another door...

The host already knows, and it most likely attempting to lure the contestant into switching. Similar happened in the film 'Slumdog Millionaire.'

[AJ010]

Yes the placement is entirely random, but given our situation where the host reveals that box 3 is a goat, and our player picked box 1 it is 50/50.
When our player picked box 1 the goat is still in box 3, do you think that just because the player cant see the goat it makes it 1/3?? No the goat didnt just magically apear when the host revealed box 3. The goat has been there all along, so given that the player picks either box 1 or box 2 from the start he has a 50/50 percent chance regardless.

It doesn't matter what box the player selects from the start. The end result is always the same: 1 goat,1 car, 2/3 chance the player picked a goat on the initial pick. Once you can understand that starting with 2 goats and 1 car affects the likelihood of even picking a goat(you are misunderstanding the consequences of this), then you will see how simple the solution I provided is.

[East1600plus]

yes u switch... your chances or winning just went from 33% to 66% so u switch

[fourhand461]

If you stay... 1/3 chance.

If you switch... 1/2 chance.

Host just showed you by opening 1 goat door that there's now a 50/50 chance of winning if you switch. If you stay, it's like he never opened the door and chances are still 1 out of 3.

[DBrickshaw]

You'd hear the goats, you're standing in front of Door #1, listen out for them..

[dfree25]

switch.. you have a higher probability of winning

this is true.. i don't know reasoning behind it. AP stats brahs should know all about this

[swoleclitorous]

It doesn't matter what box the player selects from the start. The end result is always the same: 1 goat,1 car, 2/3 chance the player picked a goat on the initial pick. Once you can understand that starting with 2 goats and 1 car affects the likelihood of even picking a goat(you are misunderstanding the consequences of this), then you will see how simple the solution I provided is.

NOO


For the host to have revealed a goat in the first place means that the player has picked between two boxes one of which is a car.

If he switches he is picking from two boxes one of which is a car.

[dzr0001]

3 Doors ( 2 goats, 1 car)
Assume the placement of goats and car is random (i.e there is no way to to know where the goats/car are likely to be placed)

Question 1) What is the probability you pick the goat on your first pick?
Answer 1) The probability is 2/3 (duh???)

Now the host removes a door(goat) for you. So all that remains is a car and a goat.

Mini-Question: Do you have a goat, or a car?
Answer Mini-Question: You don't know for sure, but what you do know is the odds you have a goat is 2/3.

Question 2) Given that you originally picked a goat, what is the probability that switching will get you a car?
Answer 2) 100%

Note: 2/3 * 100% = 2/3

Question 3) Given that you originally picked a car, what is the probability that switching will get you a car?
Answer 3) 0%

Note: 1/3 * 0% = 0

Therefore, the probability of getting a car by switching is 2/3


Simulate this via a computer program if you don't believe us. 2/3 of the time, those that switch will win the car.

http://www.grand-illusions.com/simulator/montysim.htm