Petersburgh Paradox

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  • #21629
    pacopasa
    Participant

    I’m not much of a mathematician but I do like to go to Atlantic City, so this is my take on the paradox. I suspect this approach was previously taken by someone else and I would appreciate any feedback.
    It appears to me that whatever fee one decides to pay, the odds of losing that fee(investment) is 50%.
    What are the odds of breaking even?
    If your fee is $2, the odds are 50%
    If your fee is $4, the odds are 25%
    If your fee is $8, the odds are 12.5%
    If your fee is $16, the odds are 6.25%
    If your fee is $32, the odds are 3.125%
    If your fee is $64, the odds are 1.5% (rounded)
    If your fee is $128, the odds are .75%.
    Therefore the odds of losing $128 is approx 99%, very bad bet.

    Since the odds of losing one’s fee is never in one’s favor a reasonable person would not play the game at $2. If you don’t play there is a 100% chance of keeping $2, if you play there is only a 50% chance of keeping $2.
    Playing at a higher fee is more unreasonable….
    …. on the other hand if you pay only $1 you still have a 50% chance of losing that dollar but you also have a 50% chance of DOUBLING your investment. The less you pay still keeps you at 50/50 but you can triple, quadruple… your investment.
    So I think a reasonable person could play for less than $2.
    I think the utility theory comes into play only when you change the starting amount of the game. As a middle class cautious gambler I would be comfortable paying a $20 fee for a game that started at $20 and a $50 fee for a game that started at $100.
    I would not be comfortable paying a $100 fee for a game that started at $100 or $200.

    #21630
    pacopasa
    Participant

    If the game had a four sided die instead of a two sided coin and three sides were winners, one a loser, then at a $2 game

    a $2 fee has a 75% chance of breaking even
    a $4 fee has a 56% chance of breaking even
    an $8 fee has a 42% chance of breaking even
    a $16 fee has a 32% chance of breaking even.

    A reasonable person would pay $4,
    If I had one drink I would pay $8
    If I had two drinks I would pay $16
    If I had three drinks I would pay $32
    If I had four drinks I would pass out and not play.

    The lesson: don’t drink or have 4 drinks.

    #21631
    bob.murphy.ancap
    Participant

    Hi pacopasa,

    I’m not exactly following what you are saying here. If you have a specific question can you try rephrasing?

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