Vaniver comments on Value of Information: Four Examples - Less Wrong

76 Post author: Vaniver 22 November 2011 11:02PM

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Comment author: Romashka 17 September 2016 09:03:29PM 0 points [-]

Where do you get the exact "half-chance of nothing because you don't play"? How do you decide to play or not, given a favorable outcome of the test run?

Comment author: Vaniver 18 September 2016 10:27:06PM 1 point [-]

You should play if the expected value is positive, and not if it's negative. If the test run results in heads, then the posterior probability is 2/3rds and 24*2/3-12=4, which is positive. If the test run results in tails, then the posterior probability is 1/3rd and 24*1/3-12=-4, which is negative.

(Why is the posterior probability 2/3 or 1/3? Check out footnote 3, or Laplace's Rule of Succession.)