The Monty Hall Problem

[evilbau]

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If you don't understand why it is 2/3 after reading this far in the thread, you never will.

that is only 1/3 of a line, imo

[Devek]

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If you don't understand why it is 2/3 after reading this far in the thread, you never will.

that is only 1/3 of a line, imo

Ever seen a grown man naked?

[Jeryhn]

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If you don't understand why it is 2/3 after reading this far in the thread, you never will.

that is only 1/3 of a line, imo

Oh God lol

[Millael]

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If you don't understand why it is 2/3 after reading this far in the thread, you never will.

that is only 1/3 of a line, imo

IT'S PURPLE.

[Xfaustx]

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If you don't understand why it is 2/3 after reading this far in the thread, you never will.

that is only 1/3 of a line, imo

IT'S PURPLE.

youre wrong. its 1/2 of the window size. depending on how large your window is. lets make a mathematical problem to find out the % of the line in relation to the size of your window. 1st one to figure it out gets milk and cookies from me.


*edit* i want the answer in pixels.

[Byrd]

but on the cereal side. its just like going to vegas. your odds of winning are very slim cuz the house effects the outcome. its pretty close to the same principle, but because youre dealing with smaller numbers does not make it completely solvable by math alone. there is some luck involved.

This problem is, by definition, mathematical. The question isn't whether you going to win the car or not, your question is how to maximize your odds. There is no human element to that question.

[evilbau]

******************************* <-------- this is the line

If you don't understand why it is 2/3 after reading this far in the thread, you never will.

that is only 1/3 of a line, imo

Oh God lol

glad you enjoyed that

[Seyrr]

the math makes complete sense, im not trying to argue that. im just saying that its not a perfectly mathematical world and there is human error to be dealt with. if it were perfect then yes it would be 2/3

I cannot tell you how much I hate statements like that. This is a problem with defined parameters. If you encounter it in the real world, with those parameters in place, it will be 2/3. You can't just handwave an "oh, the house is out to get you so it'll go wrong somewhere" and call that good.

There's no reason to bring human error or a cheating host or anything like that into the problem.

Sorry, it's just a real pet peeve.

[Xfaustx]

the math makes complete sense, im not trying to argue that. im just saying that its not a perfectly mathematical world and there is human error to be dealt with. if it were perfect then yes it would be 2/3

I cannot tell you how much I hate statements like that. This is a problem with defined parameters. If you encounter it in the real world, with those parameters in place, it will be 2/3. You can't just handwave an "oh, the house is out to get you so it'll go wrong somewhere" and call that good.

There's no reason to bring human error or a cheating host or anything like that into the problem.

Sorry, it's just a real pet peeve.

yeah i hate it to but its something thats to be dealt with. the main problem is how the question is stated.

the way Bryd worded it makes sense, in order to maximize your odds not to win the car.

everyones trying to answer a different question.

[Tricen]

So you're saying you should take b into consideration when doing the equation even though you know it's wrong? You have 3 doors, 3/3. You take one out so you have 2/3. But you know one is wrong so why would you count it to begin with? It is part of the problem but irrelevant? So now you have 2 doors, and one irrelevant door... Well if you have some sense in you you'll choose from the 2 doors, so 2/2? You CAN take b out of the equation because there is no point in keeping it?

You can't take B out of the equation because you already made a choice. Then the goat was revealed, and you are offered a 2nd chance.

Now, if the host had revealed a door with a goat before you chose any of the doors, then it would be 1/2 chance.

Yes you can lol. You have 3 choices, and one is revealed. Now you have to pic between 2 doors out of the original 3. Why are you applying math when you can simply apply logic? You KNOW what is behind one door, so you will disregard it. That means it is not in your thought in what you are about to chose. You will NOW chose from 2 doors. You will ONLY chose from 2 doors. Yes, you have the ability to chose from 3, but you know one isn't a winner, so WHY would you take "b" into consideration?

[aurik]

So you're saying you should take b into consideration when doing the equation even though you know it's wrong? You have 3 doors, 3/3. You take one out so you have 2/3. But you know one is wrong so why would you count it to begin with? It is part of the problem but irrelevant? So now you have 2 doors, and one irrelevant door... Well if you have some sense in you you'll choose from the 2 doors, so 2/2? You CAN take b out of the equation because there is no point in keeping it?

You can't take B out of the equation because you already made a choice. Then the goat was revealed, and you are offered a 2nd chance.

Now, if the host had revealed a door with a goat before you chose any of the doors, then it would be 1/2 chance.

Yes you can lol. You have 3 choices, and one is revealed. Now you have to pic between 2 doors out of the original 3. Why are you applying math when you can simply apply logic? You KNOW what is behind one door, so you will disregard it. That means it is not in your thought in what you are about to chose. You will NOW chose from 2 doors. You will ONLY chose from 2 doors. Yes, you have the ability to chose from 3, but you know one isn't a winner, so WHY would you take "b" into consideration?

If you were shown 3 doors, 1 of which was open and had a goat, then yes, you're just choosing between 2 doors and you have a 50/50 chance. However, you have more information than that due to your initial selection possibly restricting the host's choice of which door to reveal. 2/3 of the time, the host doesn't have a choice which door to reveal to you, this is information you can extrapolate to mean 2/3 of the time, the door he doesn't reveal must have the prize behind it.

[Xiona]

body language

assuming he will be excited for you to win you go slowly and say hmm im thinking of, door X but im not sure. as you say that look for micro expressions in his face. if you see a split second of disappointment go with the other door.

takes practice, but if he does know whats behind where you will be able to read it

[Seyrr]

Why are you applying math when you can simply apply logic? You KNOW what is behind one door, so you will disregard it. That means it is not in your thought in what you are about to chose. You will NOW chose from 2 doors. You will ONLY chose from 2 doors. Yes, you have the ability to chose from 3, but you know one isn't a winner, so WHY would you take "b" into consideration?

Except you're throwing out useful information from the past.

The information you have after B is shown as a goat: The prize is behind A or C.

The information you have from before: There is a 1/3 chance it's behind A, and a 2/3 chance it's behind B or C instead.

Combined, those give you that it's 2/3 behind C. You want us to ignore the second fact for no good reason.

[wartortle]

Abstract it to the general case. This isn't just a 3-door problem. It's an N-door problem where you open every door but one.

Assume you are again playing Let's Make a Deal, but there are 100 doors.

You pick door #13.

Now, Monty opens 98 doors and shows you 98 goats.

Do you keep your door or do you switch?

Consider that 99 times out of 100, your initial pick will be wrong. For each and every one of those 99 times, if you switch you win. The one in a hundred chance of getting the door right on your guess is the only time you lose.

Take this back down to 3 doors. Why would you ever not switch?

[Tricen]

The "useful information" you talk about is a wrong answer. You have 3 doors, one is revielded as wrong. You now have 2 doors. Now you KNOW how the game games, so what are your options? 1 door HAS a goat, the other door HAS a car. Now, you only have 2 choices. The game originally says there are 3 doors and 2 goats and 1 car. You have 1 goat out of the way. So now it is down to a goat and a car. Goat = 1 car = 1. 2/2 50% chance.

[BarthelloSylph]

Xfaustx,

On behalf of everyone here, I ask you:

Do you really believe there's an element of human error in this problem?


We're all cheering for you,

Bart

[izembo]

it's 1/2, anyone who says otherwise is wrong.

[aurik]

The "useful information" you talk about is a wrong answer. You have 3 doors, one is revielded as wrong. You now have 2 doors. Now you KNOW how the game games, so what are your options? 1 door HAS a goat, the other door HAS a car. Now, you only have 2 choices. The game originally says there are 3 doors and 2 goats and 1 car. You have 1 goat out of the way. So now it is down to a goat and a car. Goat = 1 car = 1. 2/2 50% chance.

You do indeed have more information about the state of the puzzle due to your ability to limit Monty's choice of which door to show you after your initial selection. That's why your second choice is not "A or C" but rather "A or not-A". Since you already know that A is 1 in 3 chance, not-A must be 2 in 3 chance.

The fact remains that 2/3 of the time, Monty has NO CHOICE which door to reveal after your initial selection. Therefore 2/3 of the time, the door Monty does NOT show you contains the car.

[Seyrr]

The "useful information" you talk about is a wrong answer. You have 3 doors, one is revielded as wrong. You now have 2 doors. Now you KNOW how the game games, so what are your options? 1 door HAS a goat, the other door HAS a car. Now, you only have 2 choices. The game originally says there are 3 doors and 2 goats and 1 car. You have 1 goat out of the way. So now it is down to a goat and a car. Goat = 1 car = 1. 2/2 50% chance.

... do you even read anything anyone else says? You just posted pretty much the exact same thing as in your last post, and you don't do anything to refute the points other people made besides say "nuh uh, you're wrong." Aurik makes a really good point in his last few points, but you've pretty much ignored it.

EDIT: wtf, Birdhair now? Someone else try to claim it's 1/2, and maybe I can argue up to CoP Dynamis or something.

[Xfaustx]

Xfaustx,

On behalf of everyone here, I ask you:

Do you really believe there's an element of human error in this problem?


We're all cheering for you,

Bart

who are you? i dont get it. and good luck trying to figure this out, cuz not everything can be solved mathematically. or as simple as as it seems.

your brain sir is human error >.>