April 2012 - Question 2

Discussion in 'CT6' started by jm_kinuthia, Sep 4, 2013.

  1. jm_kinuthia

    jm_kinuthia Member

    I am struggling to generate the number of decision functions required for this. Please assist.

    Also, if possible please explain concept behind this or technique required to answer such a question as am struggling to figure it out and the notes don't explain much.
     
  2. suraj

    suraj Member

    Say, Dice I is conventional dice
    and Dice II is the one with three 2's and three 4's

    Now we've to identify whether it's die I or II after being told the result.

    Although there are 64 possible decisions functions but only 4 are meaningful, because a sane person won't say it was dice II, after seeing 1,3,5 or 6.

    4 decisions functions and expected payoffs:
    d.JPG

    For calculating payoffs, say our choice was decision 1, and dice was I, so

    We would win 1 if (1,3,5,6) lands with probability 4/6
    win 0 if 4 lands with prob. 1/6
    and, win 1 if 2 comes with prob. 1/6

    So expected payoff is "5/6"
    Rest try yourself ;)

    Now minimax, expected payoff and of-course common sense! , everything tells us that decision 4 is the best choice.
     
    John Lee likes this.
  3. Keshi

    Keshi Member

    This is much clearer than the examination report answer.
     

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