Re: Today's evil Bayesian math problem

From: Eliezer S. Yudkowsky (sentience@pobox.com)
Date: Thu Sep 11 2003 - 00:16:24 MDT

  • Next message: Spike: "RE: barbie promoted to threat"

    Eliezer S. Yudkowsky wrote:
    > Suppose that a bowl has 5 red chips and 3 white chips. We sample chips
    > from the bowl using the following procedure: On each round we draw a
    > random chip, replace it, and then add another chip of the same color to
    > the bowl. For example, if on the first round we happen to draw a red
    > chip, there would then be 6 red chips and 3 white chips to draw from on
    > the second round.
    >
    > Given that a white chip was drawn on the fourth round, what is the
    > probability that a white chip was drawn on the second round?
    >
    > (This problem is extra bonus evil because it's so easy if you know the
    > rules.)

    Evil Hint #1: Not only is it possible for you to do this problem in your
    head, the answer can be obtained in ONE step.

    -- 
    Eliezer S. Yudkowsky                          http://singinst.org/
    Research Fellow, Singularity Institute for Artificial Intelligence
    


    This archive was generated by hypermail 2.1.5 : Thu Sep 11 2003 - 00:25:29 MDT