Nope

yes, thanks

El problema o la paradoja de monty hall es un error: Se basa en un error de suma: Cada puerta tiene tiene 1/3 de probabilidad, si escojo una, las otra dos tienen 2/3 de probabilidad, eso es correcto, se ha sumado las probabilidades de las otras dos puertas cerradas, pero cuando una de las dos se abre, las suma no es válida, porque es como sumar peras con manzanas… es decir la probabilidad de la puerta abierta no se le suma a la puerta cerrada… Vámonos por otro camino, supongamos que las cabras son de oro, unos 50 kg de oro, y valen mas que el carro… asi quiero es la cabra y el abre una puerta con una cabra … La probabilidad de cada puerta es de 2/3, si escojo una, las otras dos valdrán 4/3 Una probabilidad de 4/3 es superior a la unidad, lo cual es infalible, pero no es real … la probabilidad real es 1/2, porque la probabilidad cambio a abrirse una puerta … se podría decir en este caso se redujo y en el anterior aumento, ambas quedaron en ½ se igualaron entre si …

Honestly NO!!

Yeah.

Come on Captain, the night shift is keeping you and Kevin apart. You two just need to bone.

@@meowthtroplaysvideogames BONE !

How dare you detective diaz I am your SUPERIOR OFFICER

BOOOOOOONNNNNNNEE

What i do in my bedroom detective is none of your business

do a fake roar. XD

General Grievous haha i thought about it too

General Grievous IQ of 1000 right here that is actually genius

The real solution is in the comments

IQ OVER 9000

this somehow makes sense

The reason it works is because you pick a door before the host, not after. If the host were to remove a goat door first, then it's 50/50, but in this case u selected a door with 3 possible rewards, 2 out of 3 being a goat. You force the host 2 out of 3 times to remove remaining goat door, so the other door the host couldnt open must have the car behind it.

Another way to think about it is tell the audience the full sorry with the original question. The host can't pick your door weather you are right or wrong so this naturally will give the other 2 doors the better odds.

@@jdbaker82 The full SORRY?

Best

BOOOOOOOONE?!

and in the end it worked lmao i died

NINE NINE!!!

NINE NINE!

I literally saw this puzzle in the Ask Marilyn column back in the 90s.

thank you!!!!

Watched an entire 7 min video and didn't get it, you and your 2 line comment made it way clearer. Thanks !

@@lenahhhhh6568 oh my im happy for that, i dont remeber exactly, but i think this was exactly the case with me and then i tried to think about it alone and this is what i came up with

@@zxkredo yeah I had to made a schema of the situation myself ahah, real brain teaser

yeah it has a lot of uses

Panzerker milk, cheese, meat, companionship

Sara Q. As a goat owner, I can confirm it is awesome👌👌

@@dachshunddoggo2764 companionship after meat?

@@DenkyManner Well, yeah. Can't get any closer than being part of someone else.

The Alaska Zoo got started because someone won a radio contest with the prize being a choice of cash or a baby elephant. The winner chose the elephant. And yes, there's a Simpsons episode based on that.

I think the contract doesn't let you keep the zonks.

Craftee Madee u can bring more such goats by selling a car lol

Or you can buy another goat and breed a lot more

The chances to win by switching is determined by the probability of you picking a goat and the host picking a goat. The chances for you is 2/3, for the host it's 1, so the chances of winning are 2/3x1=2/3. If the host didn't know where the car is then you would be correct that it's 50/50 if he revealed a goat because the chances to win by switching are not 2/3x1=2/3 but rather 2/3x1/2=1/3, same as in staying which is 1/3x1=1/3. In one case 1/3 pick cars , 2/3 pick goats and they all continue, and in the other case 1/3 pick cars and 2/3 pick goats but only half (host reveals car half of the time when he's left with a car door and a goat door) of those that pick goats can continue.

@Klaus 74: A very well-structured explanation, thank you! There is one thing I still do not understand however. You mention that the chances of winning when you switch doors are equal to 2/3x1=2/3. In other words, the chance of winning when you switch to the other door is equal to the chance that you picked a goat multiplied by the chance that the show host picked a goat. Why is this? Maybe this is an obvious one, but like I said mathematics aren't my strong suit. I *DO* understand how this same formula changes based on whether or not the host knows the position of the car though, and how this affects the odds of winning based on whether you switch or not if he does know where the car is, but leaves it at a 50/50 shot if he doesn't. (And also imposes a chance that he reveals the car behind the door after the first pick, ending the game.) That really helped me figure this out a little better, so thank you!

Glad it helped. Another way of looking at it is this....the chances of what you pick have to be the same as the chances of what's left over for the host. So when there's a 2/3 chance of picking a door with a goat then the host must have a 2/3 chance of having a car door and a goat door left over to him from which to reveal the goat and leave the car. So there's a 2/3 chance the revealed goat is the last one.

"You mention that the chances of winning when you switch doors are equal to 2/3x1=2/3. In other words, the chance of winning when you switch to the other door is equal to the chance that you picked a goat multiplied by the chance that the show host picked a goat. Why is this?" Two events must happen in order to win the car by switching. One, you pick a door with a goat, and two the host does as well. To calculate the probability of both those events happening you need to multiply their respective chances. For you to pick a door with a goat is a 2/3 chance and the host the chance is 1 because he 'must' reveal a goat according to the rules of the problem. So when you multiply the two events by their probabilities you have a 2/3x1=2/3 chance that both of you will pick a door with goats thus winning by switching. Let's take another example. You are in a chess tournament and you have to win the next two games in order to win the championship. One of the opponents you will face is is not as good as you are and you have usually defeated him in the past, perhaps three times out of four games. So the chances of defeating him again you can estimate as a 3/4 chance. The other opponent you will face is a stronger one and you estimate your chances of defeating him is 1/2. So before you begin play against either one of them the chances of beating both of them is 3/4x1/2=3/8.

@Klaus 74 and @ Georg Cantor: That cleared it up! I understand now. It's still really bizarre to me that the math works out this way, but I get it. Thank you two for your explanation, that was enlightening!

Its easy, open all doors. You win

The video over complicated a very simple problem.

The host always opens a losing door in this scenario. Fucking obvious, Monty used to switch to winning doors. Just broads changing the rules to look smart

Here’s the quick version, if you switch, you’re basically saying, “I want to win a car if there’s a goat behind the door that I picked when all 3 doors were closed and I want to win a car if there was a goat behind the door that I picked when all three doors are closed. That means if we call our doors, “Doors: A, B & C” and the car is behind Door C, I can pick Door A and switch and I can pick Door B and switch and either way, I’ll win.

but thats another assumption of his behavior, not to mention the fact that depending on the setup, he might not have to walk over to a door, the doors might be controlled by someone in a booth.

But iocane comes from Australia, as everyone knows, and Australia is entirely peopled with criminals, and criminals are used to having people not trust them, as you are not trusted by me, so I can clearly not choose the door in front of you.

@@tomleonard830 😂😂😂

Reply

Thank you!

3 foot D.J Khaled.

i did..it was Kevin Spacey, right ?

Angan Bhattacharyya yup

Hi, can you explain, the situation in the movie? I don't remember it. Would be nice. Maybe i will see the movie again. :-)

It's in the first act when Jude Law is in Kevin Spacey's math class. Kevin Spacey literally just asks his class this problem, Jude Law gets the solution right, and then I think he leaves.

I remember that scene, but they did a poor job explaining it to the casual viewer. I was convinced that the odds remained 50/50. They should have spent an extra minute explaining WHY the odds increased, like they did in this video. :)

Average is 90 to 110. 138 is 'very superior'. Doesn't matter anyway, her IQ doesn't affect the mathematics of probability.

@braden7180 no

They say that you can win 2/3rd of the time but what about that “1/3rd”? This game is purely chance based.

@@ifisawyourreplyiwillanswerback Of course it's based on chance; no one disputes that. The question is not whether it's based on chance but does your chance improve by switching. The answer is yes, if you stay with your original choice of door, your chance remains at 1/3 but if you switch your chance is doubled to 2/3.

kevin a but what if you chose the one with the car?

Yes but after one has been revealed you have a 50-50 change, what makes switching the door better?

@@lucyrhodes7010 the host always reveals a losing door. If your first choice was a losing door and you switch you automatically win. The chance of choosing a losing door first time is 2/3. Therefore 2/3 of the times you should switch

In the MHP yes because the host knows where the car is and must reveal a goat. If he didn't know where the car is and randomly opens a door not picked by you and it has a goat then it's 50/50.

Klaus 74 Only the host has 1/2 chance of picking a goat (assuming he doesn't know where the car is), if he picks a goat, randomly or not, the chances of you getting the car if you switch remain the same in every case

What are you talking about??? If the host doesn't know where the car is then 1/3 of the time it is behind your door, 1/3 of the time it's behind the door you can switch to, and 1/3 of the time it's behind the host's door. The chances to win by switching is 2/3x1/2=1/3, same as in staying which is 1/3x1=1/3. So if a goat is randomly revealed then it doesn't matter if you stay or switch.

If you take 99 games and the host always reveals a goat then 33 pick cars, 66 pick goats and they all continue. If the host does not know where the car is 33 will still have picked cars, the host picked 33 cars and there are 33 cars (not 66) behind the door that you can switch to. All those that picked cars can continue, and half of those that picked goats can continue. 50/50.

"That means there's a 2/3 chance the car is behind one of the other two doors. Those odds don't change because Monty Hall shows a goat behind one of the doors -- whether he knows what's behind the door or not." You are wrong when it comes to the host not knowing where the car is. What's so good about leaving twice the cars for the host when half of time he leaves it for you to switch with and half of the time he reveals it?

You are doubling the chances of winning in both cases but for different reasons. In one instance the host must know where the car is and must reveal a goat in order to double the chances (otherwise it's 50/50) and in the other case swapping for the two other doors does not require of the host to know where the car is at all. One is a conditional probability problem with a subset of doors having 0 and 2/3 chances of having the car while the other is an unconditional probability problem with a subset of doors having a 1/3 and 1/3 chance of having the car.

@@klaus7443 l was implying the chance changed in anyway Klaus, more how to explain how the ratio is how it is. Imagine Monty didn't open the door until after the contestants had chosen whether to keep their original or swap. Ie Monty gives the option to keep original or opt for the other two doors and contines by saying "one of the other two is definitely a goat allow me to take it away" By doing this the odd on whether their original pick is correct haven't changed in the slightest. I thought this may have been an easier explanation of the 1/3 or 2/3 option.

@UCPsKVRwX525ZRoaISJl3Ijg Hi Klaus, I'm bot disagreeing with you in anyway. Other than, this video is about the ratio and the controversy surrounding its eventual conclusion.

I won't discourage you for it's usage then. I'm just speaking from experience in dealing with many here that know switching doubles the chances of winning but they also say it doesn't matter as to whether or not the host knows where the car is or not. If they know the answer but not the reason why then good luck in helping those that think it's 50/50 with that explanation.

Yes! That is the whole essence of the problem. And so, so many people can't see it. If contestant picks door #1, and Monty offers to let contestant swap his unopened initial choice for BOTH of the other unopened doors, it would be a very stupid contestant who wouldn't take Monty up on his offer. In regular play, that's essentially what happens.

Mr. Moji Gaming me

Me

I tried it, it's not bad

I tried it it sucks hard and you need a credit card aka its ASS

Rob Spagrenetti a 2 month free trial isn't that bad (especially if you have summer vacation)

Then you must watch the movie 'Quiz Show' starring Ralph Fiennes, based on a true story that matches your comment perfectly.....cheers!

@@klaus7443 one question tho... Why didn't you give a like to the comment?

Moon Pie Eater 50 views 78 likes sorry buddy

51 views 93 likes KZfaq is back

Losqualo Telli I’ve been scrolling through the comments and yours is the one that helped me understand, thanks

I've seen this problem before and somehow this is the first explanation that makes sense to me

Gaurav Shanbhag this cracked me up ≥3≤

Sebastian Anderson can you back that up ?? With some of the stats just curious

Naturally weird Nope, who do you think would waste time preparing statistics on that that I could send you lmao. My job is as a statistician, I know what people who deal with statistics do and do not struggle with in statistics, and at least unless American statisticians are significantly less educated than European ones I would be very surprised to hear that any of them struggle with this particular issue. If your argument is that without backing statistics I can’t make any argument, then here’s a dosey for you: since the statistics don’t exist, infographics show pulled that “fact” out of their asses too. At least I base mine on interacting with hundreds of statisticians over the years and being aware with the statistical curriculum and hence that anyone with a more than basic understanding of stats should have 0 issues with this.

The problem is too simple for statistical analysis. The simplest proof is this: 1. I f you switch you always get the "opposite" of your original pick. 2. 2/3 of the time your original pick will be a goat. 3. Therefore 2/3 of the time a switch will give you the car. (1/3 of the time you will lose by switching)

cool . i am just a high school kid and i really like probabilities so i thought maybe i could get some new insights into it.

Roger Bodey What you’ve just done counts as statistical analysis :)

That isn't realistic because the chances of what you pick are the same as the chances of what's left over for the host. Since there is a 2/3 chance of you picking a goat then must be also a 2/3 chance the host is left with a goat door and a car door from which to reveal the goat and leave the car.

Seth Webster, If the host *_must_* reveal only a goat, and never the car... then if your first choice is one of the two goats (which is a 66% likelihood), then him revealing the second goat means that the only door left is the car. If you pick a goat, and the host reveals a goat, the only door left is the car. If instead, you pick a car, and the host reveals a goat, the only door left is a goat. Thus, if you switch, the result is that you *_always_* end up with the opposite of what your first choice was. So if you know your first choice is 2/3 chance of being a goat... then switching will mean a 2/3 chance of being a car, because switching always results in the opposite.

Yes if the host knows where the car is and always must reveal a goat. If he didn't know where the car is and randomly opened a remaining door (or if the wind blew it open) and it happens to be a goat then it's 50/50.

easy as that

Since you are 1/3 likely to pick the car door ar first, the two first cases should fall into that 1/3, so each will have 1/3*1/2 = 1/6. You cannot compare those cases that have 1/6 with the others that have 1/3.

I think the first two cases are something different. Then there are 4 options and if you pick one of the first two you shouldn´t change and if you pick one of the last two you should. It is two different cases if he shows you goat one or two.

There are 4 options but two are half as likely as the other two. In order to get probabilities by counting cases you have to make sure that everything you count as a case is equally likely. If we count cases as you are doing, we are assigning two for having hit the car, and 1 for each goat, so if we played a lot of times, like 100, we should have selected the car about in 50, the goat 1 about in 25, and the goat 2 about in 25, which is absurd. There is no reason to think that we are going to hit the car door firstly more often than the other two. Imagine you played 900 times. Let's put the numbers, assuming that the sample proportions exactly match the probability, that is, you should pick each content 1/3 of the time. 1) In 300 games your door has the car. 1.1) In 150 of them the host reveals the goat1. 1.2) In 150 of them the host reveals the goat2. 2) In 300 games your door has the goat1. In all those 300 the host reveals the goat2. 3) In 300 games your door has the goat2. In all those 300 the host reveals the goat1. - If goat 1 is showed, you can only be in case 1.1) or in case 3), so you are under a subset of 450 games. You win by staying in 150 of those 450 (case 1.1) and by switching in 300 of those 450 (case 3). • 150 represents 1/3 of 450. • 300 represents 2/3 of 450. - If goat 2 is showed, you can only be in case 1.2) or in case 2), so you are under a subset of 450 games. You win by staying in 150 of those 450 (case 1.2) and by switching in 300 of those 450 (case 2). • 150 represents 1/3 of 450. • 300 represents 2/3 of 450.

Ronald I see your point...

the first two probability’s do not have the same probability’s as the rest

Bob Elogeg your forever lost comment has been commented from France.

roucoupse And now from Reunion Island,Indian ocean

Orange Juice are you really there it is beautiful

Bob Elogeg Thanks ! And yeah,I live there and I was born there :)

Ok

...

....

.....

MegaChibi ......

.......

Random Internet User I believe most people understand this theory, after all, as you also said, it's not a complex one. People are just getting it wrong the first time, because they don't really think about it and just go with their gut.

r/iamverysmart

they just word this terribly, all they have to say is, " you are more likely to pick the wrong door first, then after he removes the other wrong door, the right one will remain 2/3 of the time

Ethan Barnes I think the wording isn't that bad, sure it can be a bit confusing, but IMO i think the explanation is what confuses the regular viewer more so. I think it makes more sense by making a table with all the possibilities and then counting them to find the probability at the start and then when a goat is revealed.

Random Internet User: The question really should state whether the host chooses randomly or always chooses a door with a goat. If that's not specified, it's more natural to assume the host chooses randomly, which makes the 50/50 solution correct.

Exactly. The game has to always have the premise that you can win based on your choice. The situation can never be that you lose the game stick or switch. Monty must know since he would never reveal the car, always a zonk. Knowlege you have effects the odds.

Assuming of course, it's a female goat. You really don't want to try to milk a male goat.

But lets say that u have picked right, there are still more chances that you have picked wrong and then u would switch and lose

Monty never opens the door with the car, he always reveals a Zonk. After all, why would he pick a random door and risk the game being compromised by his choosing the car. Monty always knows (as both the host and co-creator).