Please Explain (actually explain) The Monty Hall Problem

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Discussion Overview

The discussion revolves around the Monty Hall Problem, a probability puzzle involving a game show scenario where a contestant must choose between three doors, behind one of which is a prize. Participants explore the implications of the initial choice and the information revealed by the host's actions, questioning the relevance of the first choice in determining the final probability of winning.

Discussion Character

  • Debate/contested
  • Exploratory
  • Mathematical reasoning

Main Points Raised

  • One participant argues that the first choice is immaterial and does not affect the outcome of the game, suggesting that the game continues regardless of the initial selection.
  • Another participant counters that the act of the host revealing a losing door provides crucial information that impacts the probabilities involved.
  • A different viewpoint emphasizes that the first choice does not provide relevant information, asserting that the final decision is what ultimately matters.
  • Some participants illustrate the problem using variants with more doors, arguing that the principle remains the same and that switching doors increases the chances of winning.
  • There is a contention regarding the assumption of equal probability in the final choice, with some asserting that the probabilities are not equiprobable after the host's reveal.

Areas of Agreement / Disagreement

Participants express differing views on the relevance of the first choice in the Monty Hall Problem. While some believe it has no bearing on the outcome, others argue that it does provide information that influences the final probabilities. The discussion remains unresolved, with multiple competing perspectives present.

Contextual Notes

Participants reference various scenarios and analogies to illustrate their points, indicating that the discussion is nuanced and depends on interpretations of probability and information theory. There are unresolved assumptions regarding the nature of the game and the implications of the host's actions.

  • #91
FactChecker said:
Yes, it does make a difference. There is a difference between an accidental result of rare luck versus the intentional act of avoiding opening one door. Consider the example (again) of the game with 100 doors. In the first case of luck, the only inference that can be made from opening 98 doors without revealing the prize is that a rare, lucky event was just witnessed.
The host must know the car location to comply with the rules:
1. Host cannot open a player door choice until after player last choice.
2. Host cannot open a car door until after player last choice.
The game rules prevent the host from accidently revealing the car location, ending the game, and denying the player a 2nd choice.

If player chooses a car door, it survives by rule 2.
If player chooses a goat door, it survives by rule 1.
The host opening 98 goat doors does not change the contents of any doors.
All goat doors are identical thus they have no special status.
The end result is 1 car door and 1 goat door with the player not knowing which one wins.

This is equivalent to tossing a coin.
 
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  • #92
phyti said:
The host must know the car location to comply with the rules:
1. Host cannot open a player door choice until after player last choice.
2. Host cannot open a car door until after player last choice.
The game rules prevent the host from accidently revealing the car location, ending the game, and denying the player a 2nd choice.

If player chooses a car door, it survives by rule 2.
If player chooses a goat door, it survives by rule 1.
The host opening 98 goat doors does not change the contents of any doors.
All goat doors are identical thus they have no special status.
The end result is 1 car door and 1 goat door with the player not knowing which one wins.

This is equivalent to tossing a coin.
Are you saying that if you stick with your original choice then you win 50% of the time?
 
  • #93
phyti said:
The host must know the car location to comply with the rules:
1. Host cannot open a player door choice until after player last choice.
2. Host cannot open a car door until after player last choice.
In the Monte Hall game, the player only has one choice that he does before Monte opens any door.
phyti said:
The game rules prevent the host from accidently revealing the car location, ending the game, and denying the player a 2nd choice.

If player chooses a car door, it survives by rule 2.
If player chooses a goat door, it survives by rule 1.
The host opening 98 goat doors does not change the contents of any doors.
All goat doors are identical thus they have no special status.
The end result is 1 car door and 1 goat door with the player not knowing which one wins.

This is equivalent to tossing a coin.
So you don't think that Rule 2 and the fact that Monte did not open that remaining door gives any sort of hint that should be used to adjust the odds but that same implication does not apply to your door? As has been explained dozens of times on this thread alone, you are wrong.
 
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  • #94
phyti said:
The end result is 1 car door and 1 goat door with the player not knowing which one wins.

This is equivalent to tossing a coin.
Except that you can be objectively shown to be wrong.

The simulation in post 27 proves that switching dors will result in winning twice as often.
If your logic/intuition do not lead to that result, then it is demonstrably faulty.
 
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  • #95
phyti said:
The end result is 1 car door and 1 goat door with the player not knowing which one wins.

This is equivalent to tossing a coin
Only if the two options are equal probability, which they are not. Simply having two options does not mean that the probability is 1/2

https://www.ac-psych.org/en/download-pdf/volume/10/issue/4/id/164
 
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