• St Peterburg Paradox

    From David Entwistle@qnivq.ragjvfgyr@ogvagrearg.pbz to rec.puzzles on Thu Dec 11 15:06:08 2025
    From Newsgroup: rec.puzzles

    Not a puzzle, but a question about a paradox, which forms part of a
    puzzle.

    Does anyone have access to the a translation of the original Petersburg Paradox, or anything relatively definitive describing it, or know it well enough to describe it?

    I read about this paradox in Martin Gardners "Mathematical Puzzles and Diversions" (pg. 53), but wasn't happy with the description, nor the
    answer provided, nor the preceding paragraph on Mr Smith's children.

    I've read the Wikipedia page:

    https://en.wikipedia.org/wiki/St._Petersburg_paradox

    but the answer provided, that the expected value (E) is given by:

    E = 1/2 x 2 + 1/4 x 4 + 1/8 x 8 + ... 1/n x 2^(n-1)

    doesn't seem right. As I understand it, there's only one payout per game,
    so you shouldn't add the series of probability-of-payout x payout, for all rounds. I'd expect the expected value is just the value of one of those
    terms, which removes the paradoxical conclusion that the expected value is infinite.

    https://en.wikipedia.org/wiki/St._Petersburg_paradox

    I think I must be misunderstanding the description of the game.

    Thanks,
    --
    David Entwistle
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