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| Almost Anything Goes In here you can chat about anything from the queen's head to the taste of mild cheddar. Just use some decency. |
| View Poll Results: What do you do? | |||
| Stick with my original choice. |
   
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17 | 68.00% |
| Switch to door number Three. |
  
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8 | 32.00% |
| Voters: 25. You may not vote on this poll | |||
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#1
8th November 2010, 07:44 AM
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Probability question.
No doubt some of you will have heard this before. Or maybe even most. Anyway, suppose you are on a game show and the prize you want to win is a PS3. The PS3 is behind one of three doors. Behind the other two doors are snakes. You pick door number One. The host doesn't open that door. Instead he opens door number Two, which he already knew to be a snake. He offers you the choice to pick door Number Three instead, or stick with your original choice.
What do you do? Last edited by Oz the Gay and Powerful; 8th November 2010 at 10:12 PM. 
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#2
8th November 2010, 07:48 AM
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Answered.
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Last edited by Mr 3vil; 8th November 2010 at 07:58 AM.
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#3
8th November 2010, 07:49 AM
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Why is that?
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#4
8th November 2010, 07:51 AM
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Quote:
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Last edited by Mr 3vil; 8th November 2010 at 07:59 AM.
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#5
8th November 2010, 07:52 AM
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Stick with your original answer; the probability of it being correct in a multiple choice answer is high. Or; alternatively...pick (c)
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#6
8th November 2010, 07:55 AM
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You would be surprised how many people get this wrong, 3vil. Nature just did.
Last edited by Oz the Gay and Powerful; 8th November 2010 at 07:58 AM.
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#7
8th November 2010, 07:56 AM
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Forty-two.
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Last edited by Mr 3vil; 8th November 2010 at 08:04 AM.
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#8
8th November 2010, 08:00 AM
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Why wouldn't it be 50/50 shot between Door 1 and Door 3 at that point? Mr. 3vil's answer makes no sense to me.
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#9
8th November 2010, 08:00 AM
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@3vil: Well we're bound to see a post which holds the answer... I didn't think it would be three posts in.
 But thank you.edit: Well since Avarice caught the answer but didn't understand (which is perfectly understandable), I'll explain it further. Spoiler: (highlight to view)
It isn't 50/50 because the host removed a variable. You have 1/3 odds of picking the PS3 and 2/3 odds of picking a snake. Therefore the odds that you've picked the snake on you first guess are higher than the PS3. You have a better chance of picking the PS3 by switching. A more detailed explanation would be this: The chance of you picking a snake is 66%, and the chance of you picking the PS3 is 33%. The host shows you a snake, and the switch raises your odds of picking the PS3 to 66%, and lowers the odds of picking the snake to 33%, since it is likely your first pick was the snake anyway.
A spoiler tag is fair this early in the game I think Last edited by Oz the Gay and Powerful; 8th November 2010 at 08:08 AM.
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#10
8th November 2010, 08:06 AM
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You could have made this poll last longer. My posts are now random as Hell. Clearly the answer is 42.
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#11
8th November 2010, 08:07 AM
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On your first guess yeah of course there is a 2/3 shot of getting a snake.
But when he asks you to switch to Door 3 at that time isn't it a 50/50 shot? Either your door has the PS3 or it has the snake. If your Door has the other snake, then you know Door 3 has the PS3. Two options, both equally possible ONCE THE FIRST SNAKE IS REMOVED.
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#12
8th November 2010, 08:11 AM
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No, the variables don't suddenly become 1/2. You're not thinking about the first door you've chosen. The odds that you've chosen a snake in the first place are higher than that of the PS3, therefore switching would increase your odds of picking the PS3. I've edited my previous post to make it clearer.
Quote:
Last edited by Oz the Gay and Powerful; 8th November 2010 at 08:15 AM.
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#13
8th November 2010, 08:19 AM
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Spoiler: (highlight to view)
So wait... If I were to explain this with math, it would be
[chance of initially getting a snake] / [number of unique choices] = [Percent chance your first guess holds the other snake] .66/2=.33 EDIT: Confused percents with whole numbers there for a moment. EDIT 2: No wait I am screwing this up hold on. EDIT 3: Wow that was embarrassing. I'm not a mathematician for a reason. EDIT 4: Now that I think about it some more, and am not drained from a long day's work on a lack of sleep, I was right in the first place. It's a 50/50 shot. Not a 33/66 shot. Last edited by Avarice; 8th November 2010 at 04:07 PM.
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#14
8th November 2010, 08:31 AM
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Quote:
 Oh, I see, well, remove the parenthesis. Now that I think about it, the whole math itself doesn't make sense at all.
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Last edited by Mr 3vil; 8th November 2010 at 08:38 AM.
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#15
8th November 2010, 02:03 PM
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this is one'a them there math-ee-matical tricks, innit?
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RWPARODY 3 IS BACK!
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