Sheep or a Car

[Mo0o]

Whether the alternatively choices are being shown deliberately or randomly makes a big difference

 

[RaistlinZ]

This is the kind of math that was fun to do back in school. Too bad all mathematics can't be taught in such a manner.

After reading the whole article, it does make sense that switching would give you 2/3 chance of winning. The funny thing is that most people in this real life situation would probably stick with thier initial pick, thinking that their "intuition" of thier original pick is somehow superior to swtiching.

Poor suckers.

 

[TheChort]

Since this is easy to do IRL (unlike some other threads we have had ), I did this one with my sister just now.
Granted, this is fairly crude, but it is some kind of result.

Here's what I did:
I had 3 DVD boxes opened up, standing. While she was watching TV and not paying attention to me, I put an orange behind one of them. We did 37 attempts where she didn't switch her answer, and 35 attempts where she switched her answer.

Whether or not she picked the right answer on her first guess, I always deliberately showed an empty box.

That means, if she picked the right box, but switched her answer, she would automatically be wrong. If she picked the wrong box, but switched her answer, she would automatically be right, because I would already reveal the other wrong answer.

RESULTS

Switching
Win: 21/35 = 60%
Loss: 14/35 = 40%

Not Switching
Win: 10/37 = 27%
Loss: 27/37 = 73%

 

[iamaelephant]

Originally posted by: TheChort
Since this is an easy to do IRL (unlike some other threads we have had ), I did this one with my sister just now.
Granted, this is fairly crude, but it is some kind of result.

Here's what I did:
I had 3 DVD boxes opened up, standing. While she was watching TV and not paying attention to me, I put an orange behind one of them. We did 37 attempts where she didn't switch her answer, and 35 attempts where she switched her answer.

Whether or not she picked the right answer on her first guess, I always deliberately showed an empty box.

That means, if she picked the right box, but switched her answer, she would automatically be wrong. If she picked the wrong box, but switched her answer, she would automatically be right, because I would already reveal the other wrong answer.

RESULTS

Switching
Win: 21/35 = 60%
Loss: 14/35 = 40%

Not Switching
Win: 10/37 = 27%
Loss: 27/37 = 73%

Pwnt.

 

[chrisms]

Originally posted by: Malak

Originally posted by: iamaelephant
I'm done trying to explain this to you. You're ignorant, arrogant, stupid and the worst thing is you think you're smart. You are too stupid to understand something that has been explained in plain English. I have come across paper weights with more brain power than you. Good day sir.

I don't know why you have to continue to insult me, it doesn't help your arguement any. Furthermore I should like to refer to the part in the article where people much smarter than you or I disputed this as well.

The smarter people ended up apologizing to her and saying she was right

 

[Killerme33]

Having 3 doors makes it seem like you have a 50% chance when you really don't. Try thinking about it with 4 doors (1 car 3 sheep). You pick a door, then the host opens 2 doors revealing two of the sheep. Do you switch?

 

[chrisms]

Also I'd like to add that before you say everyone is wrong and that the chances are 50/50, read the entire Wikipedia article with an open mind. If your mind is not changed after that well then there is no hope for you

I think QED put it very well, better than the Wiki article even. The opening of the door is irrelevant, as no matter what you pick the host can open a sheep door.


BTW sorry for confusing this by changing the animal, I didn't want the first responders to be able to look this up with Google.

 

[Phru]

Originally posted by: iamaelephant

Originally posted by: Malak
The reasoning behind the explanation is stupid and I will continue to dispute it. You are left with only 2 choices, the third choice is now moot and cannot be even considered in your decision. It is a 50/50 chance and there is no reason to switch nor to not switch. It comes down to chance. You have zero advantage.

Wow. You need your head examined. Go and read the article again. And again and again and again until your understand it.

Wait, you're a Christian right? Hhmm, explains a lot.

What the hell does that have to do with this? Way to be a douche bag.

 

[SearchMaster]

Hey Malak, how many people must gather in a room to have a 50/50 chance that two of them will share a birthday? Hint: it's nowhere near 2/365.

 

[Kwaipie]

Originally posted by: SearchMaster
Hey Malak, how many people must gather in a room to have a 50/50 chance that two of them will share a birthday? Hint: it's nowhere near 2/365.

if I recall, isn't the answer 31?

 

[SearchMaster]

Originally posted by: Kwaipie

Originally posted by: SearchMaster
Hey Malak, how many people must gather in a room to have a 50/50 chance that two of them will share a birthday? Hint: it's nowhere near 2/365.

if I recall, isn't the answer 31?

Even though I wrote the problem poorly, the answer is not 31.

 

[shortylickens]

It seems some people here get it and some do not.
Mathmatically it makes sense to switch and under normal common sense it does not.
Since the question has a real-world basis (game shows) and actual experiments have shown you do much better to switch, a practical person ignores common sense and goes with the best odds from real life.

I am one of the folks who favors good sense over common sense. I dont even care about the math that much.

EDIT: Incidentally, all the folks engaging in a pissing contest on the internet have shown a serious lack of brain power.
This is much like gun control or any similar debate: The people who believe in one side are not going to be swayed by the other side, they will just get madder.
The people who were not sure to begin with are likely to be disgusted with both sides and end up figuring it out for themselves.
(Or trust the one person who wasnt being a jackass in this whole thread.)

 

[BrownTown]

This thread is gonna end up just like the airplane on a treadmill thread. There is a simple accepted answer that is right, and yet a bunch of stupid kids on the interweb think they are somehow more intellegent than the rest of the world just because they got straight A's in school. The fact is that mindlessly yelling out an answer without thinking about it is silly, but FAR FAR FAR worse is sticking to your guns after the correct answer has been presented. It does not make you look confident or intellegent to continue the argument when you are wrong, it jsut makes you look stubborn and stupid. It is like running into a brick wall and then thinking if you just keep running into it again it will eventually go away. The fact of the matter is that there is a single truth here, this is not politics, its is not philosophy, you cannot argue with the answer here unless you wish to prove the entirety of our knowledge of physics, probability, math, etc wrong.

When I read this problem, and when I read the airplane problem, and many other brain teasers I got them ALL WORNG. Now ask yourself who looks dumber, they guy who admits he is wrong and accepts reality, or the guy who keeps arguing to avoid ever admitting he was wrong?

 

[mercanucaribe]

When you choose, you have a 1/3 chance of being right.
After the host eliminates one door, you still have a 1/3 chance that the door you picked was right.
Even at this point, switching to any of the other two doors gives you a 1/3 chance-- of course you can only pick one of them because the host eliminated the other.
The one you can switch to has a 2/3 chance of being the right door.

 

[UncleWai]

What if I prefer to win a sheep instead of a car? If I get the car, I actually lost?

 

[mobobuff]

In fairness to the nay sayers, this is much harder to accept than the plane taking off. I think, anyway. I was sold on the plain taking off after a minute of thinking about it, but this problem had me second guessing things for a while. Some parts I still don't quite understand (like how you can let the remaining door from a set of two inherit the group's 2/3 odds, when the situation never allows you to pick two doors at the same time anyway). I think about it as the numerator being the number of doors you can pick, and the denominator the number of doors you're allowed to pick from. I'm not arguing, because the facts are overwhelming.

It is much easier to interpret the guesser's ultimatum as a new guess at two doors. One door with a goat and one with a car. 50/50. But you're missing something when you assume that, something very important. Just like when you're assuming a speed-matching treadmill and an airplane cancel each other out, 1-1=0. You're missing the bigger picture.

 

[BigJ]

Originally posted by: mobobuff
In fairness to the nay sayers, this is much harder to accept than the plane taking off. I think, anyway. I was sold on the plain taking off after a minute of thinking about it, but this problem had me second guessing things for a while.

Both problems are non-intuitive. The key to both problems is finding an example you can understand/relate to. That's why the Wiki article is very nice on this problem, providing a couple of different examples.

 

[mobobuff]

Originally posted by: BigJ

Originally posted by: mobobuff
In fairness to the nay sayers, this is much harder to accept than the plane taking off. I think, anyway. I was sold on the plain taking off after a minute of thinking about it, but this problem had me second guessing things for a while.

Both problems are non-intuitive. The key to both problems is finding an example you can understand/relate to. That's why the Wiki article is very nice on this problem, providing a couple of different examples.

Yep, Wiki breaks it down nicely, I completely understand it now and have no more questions.

 

[imported_Ned Flanders]

But I want the Goat.

 

[slayer202]

Originally posted by: mercanucaribe
As soon as I read that the game show host knows which door has one, I realized that that is the key.. Either you picked the car and the host picked the door to open randomly, or you picked a sheep and he had to pick the sheep instead of the car. I don't know the math, but it feels to me like your odds are better if you switch.

This helps, but I am still skeptical.

Let's say the situation is the same. However, you do not pick a door until the host takes away one of the sheep. You now have a 50% shot at it. What makes this choice any difference than if you had picked in the beginning?

 

[AkumaX]

it's easier to imagine if you use 10,000 doors:

Let's say you're on a game show, and you're given the choice of 10,000 doors: Behind one door is a car, and behind the others, sheep. You pick a door, say #1, and the host, who knows what's behind the doors, opens 9,999 doors with sheep, except for, say #2, He then says to you, "Do you want to pick door #2?" Is it to your advantage to switch your choice?

 

[fuzzybabybunny]

I woulda kept the sheep. Sheep are fluffy

 

[DaShen]

Originally posted by: PhattyB
There is no advantage. All it does is gaurentee you have a 50% chance of winning some sheep love.

Nope, wrong.

It goes from 1/3 to 1/2 chance if you switch.

 

[fuzzybabybunny]

Originally posted by: DaShen

Originally posted by: PhattyB
There is no advantage. All it does is gaurentee you have a 50% chance of winning some sheep love.

Nope, wrong.

It goes from 1/3 to 1/2 chance if you switch.

Erm, that's what he said.

 

[jman19]

Originally posted by: Malak

Originally posted by: iamaelephant
I'm done trying to explain this to you. You're ignorant, arrogant, stupid and the worst thing is you think you're smart. You are too stupid to understand something that has been explained in plain English. I have come across paper weights with more brain power than you. Good day sir.

I don't know why you have to continue to insult me, it doesn't help your arguement any. Furthermore I should like to refer to the part in the article where people much smarter than you or I disputed this as well.

You might be a genius, but you aren't educated. See the Wiki article for several clear explainations.