+ Reply to Thread
Results 1 to 3 of 3

Thread: Cup and ball game: what are the odds of that?

  1. #1
    Points: 2,768, Level: 32
    Level completed: 12%, Points required for next Level: 132

    Location
    New Zealand
    Posts
    23
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Cup and ball game: what are the odds of that?




    OK we are having an intelectual discussion (no, really) about the change in odds during the classic cup and ball game. To explain:
    • a dealer has three cups under one of which is a ball
    • you pick one
    • the probability at this stage of winning is 1 in 3
    • the dealer then guarantees they will remove an empty cup

    If the "experiment" remains unchanged the probability at this stage, as I understand it, is 2 in 3 as your cup is one of the two remaining cups which must have the ball underneath.

    If, however, you change your mind (equivalent to a post-hoc analysis) then you change the game and essentially the probability becomes 1 in 2.

    Can someone with a bigger brain than mine confirm or deny this?

    Thanks.

  2. #2
    TS Contributor
    Points: 4,330, Level: 41
    Level completed: 90%, Points required for next Level: 20

    Location
    MD
    Posts
    388
    Thanks
    0
    Thanked 6 Times in 6 Posts
    http://en.wikipedia.org/wiki/Monty_Hall_problem

    You have discovered the monty hall problem (c 1990).

    turns out you should switch , gives you chance of 2/3 of winning.

    Their is alot of interesting history tied to this problem as well, the person who solved this apparently put alot of phd's in their place!


  3. #3
    Points: 2,768, Level: 32
    Level completed: 12%, Points required for next Level: 132

    Location
    New Zealand
    Posts
    23
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Thumbs up Thanks!


    Mate that's awesome. The link explains things very well.

    Guess we can lock this thread off now.

    Thanks.

+ Reply to Thread

           




Similar Threads

  1. Replies: 0
    Last Post: 01-05-2011, 11:54 PM
  2. ball game
    By initialize in forum Probability
    Replies: 0
    Last Post: 03-02-2010, 09:11 PM
  3. Football game!
    By statisticgirl in forum Probability
    Replies: 3
    Last Post: 08-31-2009, 01:47 PM
  4. Picking a ball you've picked before
    By tuna in forum Probability
    Replies: 2
    Last Post: 03-27-2009, 02:07 PM
  5. Replies: 5
    Last Post: 12-10-2008, 02:44 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts






Advertise on Talk Stats