Epic Perfect World

Monty Hall Problem

It's just psyhology and math all together
If u remove 33,3% leaves u with 66,6% chance that one of those 2 left is the good one, if he tells u to change, he just tests u, and most people choose to stay, but if u change it, u purely do what he wasn't expecting, do what he says.Most people don't wanna do what some1 tells them to do, so he tells u that, to make u feel more confident about ur door.In the end, if u change, u just get a higher chance of geting the prize, i can't explain it as i really believe since my english isn't good enough for me to say all i'd like to.In general, i'd change because humans tend to do what they are not told to. If he tells u to switch, he just tries to make u stay at the same door as u are.
Hope that what i've said made any sense, if not, sorry.
Yea, I agreed. I like how you connect it with psychology as I have never thought about it before.
Assuming you can ask him questions, ask him where is the right door and where is the wrong door - then let him talk the whole show and count how many times he says the name of each door - the one that has been mentioned the most is probably the one with the car.
Well, even if the participant is a psychologist, there's still a chance that he makes a wrong judgement, regardless his observation of the host's body language. Of course, factoring in the ability/background of the participant will definitely complicate this problem.

Also, it makes sense to think the game show host must have been professionally trained, so he will know it when someone is trying to trick him with the way you mentioned. So, your strategy wouldn't be guaranteed to work.
1/3 - Probability of getting car.

1/2 - Probability of getting car after first door is opened.

1/2 - Probability if you change.
This is where the debate comes in. Let me explain it to you:
Let's label the door with 1,2,3 ; c = car, g = goat
There are only 3 possible scenarios for this problem, each with an equal chance of 1/3 of happening:
scenario 1: 1c 2g 3g
scenario 2: 1g 2c 3g
scenario 3: 1g 2g 3c

Suppose you choose door 1 and you don't know what's behind it, then the host opens another door, says door 3 and reveals there's a goat behind it. The host asks you whether or not you want to switch to door 2, which is still unknown.

Based on the total 3 possible scenarios, the scenario described above is matched with scenario 1 and scenario 2, and we know one thing for sure, that is scenario 3 did not happen since door 3 doesn't have a car. Putting it in simple words, you just made a decision such that scenario 3 will never happen, by choosing door 1 at the beginning, and the chance for it is 2/3 (2 out of the 3 scenarios match it).

Now, don't forget among scenario 1 and scenario 2, only scenario 1 has door 1 with a car, so the chance for it after eliminating door 3 is 1/2. BUT, you cannot just eliminate door 3 from air, you need to be in that 2/3 chance which we just explained above, in order to eliminate door 3 from your option. So, finally 2/3*1/2=1/3 = chance of door 1 having a car in the above scenario; that means after the host reveals door 3 which has no car, the chance of having a car behind door 1 still doesn't chance, it is still 1/3...And this leads us to a conclusion that the remaining door 2 has 2/3 chance of having a car, since the remaining 2/3 chance has to go somewhere...and door 2 is the only remaining door after door 3 is opened.

I hope this explains well enough for you.  :smiley:

Offline Mr. Rodriguez

  • Major in Bending
  • Byte my 8-bit metal as
For people that don't like reading a lot:

Last Edit: June 20, 2014, 03:33 pm by PinkPony

Offline DignityPK

  • avatar
  • Member
  • Faction: Factionless.
For people that don't like reading a lot:


This is retarded and not even mathematical, why would you exactly switch from C to B instead of C to A, you just made 66.6% of all switches a win, while ignoring the fact that there are 3 doors, not 2. GTFO, this is bullshit.

Ignore that post ^ I didn't read OP's post right, he said the man would open the door with the goat first and show you that there is a goat and then ask you... This is just stupid, the whole point of this post is to read carefully.

scatterer3

If he is forcing you now (after you saw door no. 3 got a goat) to door no. 2, then the 2nd chance you got won't really help you out. Your chances increased from 33.33% to 50% but you're still "forced" to lose (because he will lead you always to the goats). A third chance is something else. If no. 3 is still closed and you get the offer to change to any other door, then I think I personally wouldn't make a change, since it's basically the same thing, 33.33% to win, which still doesn't mean my decision is the best possible decision, the offer to change is really confusing.

Offline Mr. Rodriguez

  • Major in Bending
  • Byte my 8-bit metal as
This is retarded and not even mathematical, why would you exactly switch from C to B instead of C to A, you just made 66.6% of all switches a win, while ignoring the fact that there are 3 doors, not 2. GTFO, this is bullshit.

Ignore that post ^ I didn't read OP's post right, he said the man would open the door with the goat first and show you that there is a goat and then ask you... This is just stupid, the whole point of this post is to read carefully.

Duude, calm your tats. I didn't kill your AFK toon or something. Player chooses a door, then host opens a goat door.