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Subject: Re: 9 rounds will not always give you the "best" program

Author: Sune Fischer

Date: 05:26:42 01/21/03

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On January 20, 2003 at 21:15:53, Dann Corbit wrote:

>>But what you were saying was, that you could _never ever_ know the answer. There
>>is a fundamental difference I think and this is where the null event theorem
>>saves us. It _is_ possible to make an accurate statement if you have reduced it
>>to a null event. After 1 trillion games I think we have a clear winner, whom
>>ever that may be.
>
>I would be utterly astonished if it were true.
>
>After a trillion coin flips, we will still have random walk problems, and it
>could (on rare occasions) be considerable.  How will we discern the random walk
>drift from a very tiny change in strength?  At the top, the strength of the
>programs appears to be very close.  This is the exact region where random walk
>will give us the most trouble.
>
>In other words, I think we will not be able to discern (on a blind test) whether
>we pit top program A against top program B or whether it was A against A or B
>against B.

Well, first step is to agree that they can't be equally strong, that would be a
null event so it doesn't happen.

Ok, the probability of a Tiger win is p in [0;1].

This gives us a serie of Bernoulli experiments.

With such a sequence of Bernoulli experiments you have the "the law of great
numbers" (not sure what's it's call in english).
It states, to make it short, that

for all epsion>0 limes n->0 Prob(abs(S/n-p))>epsilon)=0 .

In other words, going towards infinity we find p, as an exact result.

Of course it is a theoretical result, but there is an enhanched version more
complex (I will spare you the details, has to do with Chebyshev's inequality)
where you only do a limited number of trials and get a delta on the estimation.

-S.



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