Pick the Door

4,970 Views | 86 Replies | Last: 11 yr ago by Out in Left Field
Thomas Sowell, PhD
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You are on let's make a deal. There are three doors. Behind one door is a brand-new car behind the other two doors are goats. The host of the show knows exactly what's behind each of the doors. You pick your door. He then opens up one of the doors revealing a goat.
You are then asked whether you would like to stick with your door or switch to the other door that you did not choose.

Would it be to your advantage to switch doors?
FOUR THIN INCHES
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Yes
Thomas Sowell, PhD
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If yes how much do you increase your odds by changing ?
Chicken Dance
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I agree with FTI.
Chicken Dance
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You increase your odds by 33%
Mucho austin
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Are you on the game theory chapter in your Econ book?
Thomas Sowell, PhD
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No correct answers yet.
COOL LASER FALCON
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**** the goat, marry the car, kill door 3
FOUR THIN INCHES
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You increase your odds from 33% to 50%.
ajn142
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What if I find goat tasty, and consider all possibilities a win?
who?mikejones
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http://m.youtube.com/?#/watch?v=tvODuUMLLgM
Pollo Libre
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quote:
**** the goat, marry the car, kill door 3
Dr. Not Yet Dr. Ag
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I'd stick with my door, and make some cabrito
B-1 83
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One of you smart young whipper snappers explain the answer. You have one of the two doors. The car is behind one of the two. It would seem the odds are 50/50 you have the car.
ClickClack
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nvm misread it
JambiAg
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quote:
**** the goat, marry the car, kill door 3




ClickClack
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ok no it doesn't increase your odds to change. Either way, you've picked one out of the two remaining doors.
htc0008
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If I recall correctly it's about a 17% increase over staying with your first choice.
BackwardsInBoots
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When you first picked you had a 2/3 chance of picking a goat. Now that one goat has been revealed, you switch, because you were more likely at first to have picked a goat than you were to have picked the car with your first choice.
Chicken Dance
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If you stay with your answer you have a 1/3 chance to have guessed correctly. If you switch, you will only be wrong 1/3 of the time (and correct 2/3 of the time).
Claude!
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The lady or the tiger?
Dr. Not Yet Dr. Ag
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Chicken Dance is correct. Initial odds are 1/3. The host has to pick between the two other doors and has to choose a door that contains a goat no matter what is behind the door you chose, which means we learn nothing about the initial door we chose that would change its odds of being correct. Those two doors have a cumulative 2/3s chance of having the car behind it. By guaranteeing that one of those two doors does not have the car behind it, there now becomes 2/3s chance that the unopened door you did not choose is the correct one, while you are still stuck at 1/3 odds on your initial door.
BackwardsInBoots
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I agree with Chicken Dance and NYDA
Ag_EE
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Mensa
Tomdoss92
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quote:
A boat's a boat but the mystery box could be anything. It could even be a boat! You know how much we've wanted one of those. We'll take the box.
Doctor Rosenrosen
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Yep, Chicken Dance and the (NY)Doc have it. If you decide a priori to ALWAYS switch, the only way you lose is if you initially pick the car, which is 1/3 of the time. Switch!
OCEN99
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Monty Hall problem explained
Beer Baron
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How big are the goat's tits?
Thomas Sowell, PhD
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Congratulations Chicken Dance

That question was tough.
Dr. Faustus
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Can't decide this without a Rule #1.
Thomas Sowell, PhD
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Of course if you wanted a goat instead ....
Chicken Dance
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My life is complete.
Tagguy
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quote:
**** the goat, marry the car, kill door 3


The only correct answer
80s Guy
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quote:
quote:
**** the goat, marry the car, kill door 3


The only correct answer
toucan just popped a major chub!
oldschool87
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You removed a set from the equation. The Odds are now 50/50.

Thats like saying all 3 doors are open and you picked the car, your odds of winnng the car are still 1 in 3.

The orginal odds were 1 in 3 as there were 3 unknowns, but one of the unknowns is a given. You can't add or subtract data and have the equation remain the same.
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