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Get Those Brain Cells Working: The Monty Hall Problem

posted by janrinok on Friday July 29 2016, @10:27AM   
from the something-to-think-about dept.

An Anonymous Coward writes:

Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you, "Do you want to pick door No. 2?" Is it to your advantage to switch your choice?

Do any of you have any noteworthy experiences where knowledge of math helped you in an unusual way?

https://en.wikipedia.org/wiki/Monty_Hall_problem

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Original Submission

• Re:Simulation of the game Re:Simulation of the game (Score: 3, Interesting) by gringer on Friday July 29 2016, @01:22PM

  by gringer (962) on Friday July 29 2016, @01:22PM (#381518)

  non-recursive R version, for those who had difficulty understanding the Haskell version:
  
  #!/usr/bin/Rscript
  system.time({
          attempts <- 10000000;
          car <- sample(1:3, attempts, replace=TRUE);
          choice <- sample(1:3, attempts, replace=TRUE);
          stayWin <- sum(car==choice);
          swapWin <- sum(car!=choice);
          cat(sprintf("Stay winning percentage: %0.2f%%\n",stayWin/attempts * 100));
          cat(sprintf("Swap winning percentage: %0.2f%%\n",swapWin/attempts * 100));
  });
  

  Output:
  
  Stay winning percentage: 33.34%
  Swap winning percentage: 66.66%
                User System verstrichen
              0.560 0.092 0.653
  

  --
  Ask me about Sequencing DNA in front of Linus Torvalds [youtube.com]

  Parent

  Starting Score:	1		point
  Moderation		+1
  Interesting=1, Total=1
  Extra 'Interesting' Modifier		0
  Karma-Bonus Modifier		+1
  Total Score:		3

• Re:Simulation of the game (Score: 2) by JoeMerchant on Friday July 29 2016, @03:01PM

  by JoeMerchant (3937) on Friday July 29 2016, @03:01PM (#381554)

  This statement makes it clear for me:

  swapWin - sum(car!=choice);

  If you pick the car the first time, then swapping will cause you to lose, but if you pick a goat the first time, then swapping will cause you to win.

  --
  Україна досі не є частиною Росії Слава Україні🌻 https://news.stanford.edu/2023/02/17/will-russia-ukraine-war-end

  Parent