Re-Statisitics puzzle i0524

Joanne_Ownbey at CBRC.MGH.HARVARD.EDU Joanne_Ownbey at CBRC.MGH.HARVARD.EDU
Wed Jun 15 05:54:56 EST 1994


                    6/15/94                                  6:42 AM
                    Re:Statisitics puzzle i05244c
        Hey, dude*
Sean Eddy wrote:

>When we see west lead the ace of diamonds, the probability that he
>holds the ace of hearts drops to 2/3 [(from 3/4)] , because the
likelihood of our
>data given the model that he holds only the ace of hearts then becomes
>0.

>The 50/50 answers (or 48/52 answers) are intuitively unreasonable; we
>*do* have information that west has at least one red ace, which must
>increase the probability that he holds the ace of hearts. The model in
>which east got both red aces is eliminated by the data.

Being mathematically challenged- I'm confused.  How can the probability
that he holds the ace of hearts go up and down?  Also, unless the ace's are
somehow linked why should the fact that west holds the ace of d. influence
whether he holds the ace of hearts, (other than by cutting the possibilties
(ie, number of cards he holds) down by one?

Joanne Ownbey   






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