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Subject: Re: Maybe a stupid experiment...

Author: Robert Hyatt

Date: 21:00:39 01/03/01

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On January 03, 2001 at 17:50:38, José Carlos wrote:

>On January 03, 2001 at 16:26:19, Robert Hyatt wrote:
>
>>On January 03, 2001 at 09:52:06, José Carlos wrote:
>>
>>>  Lately, people have been talking here about significant results. I'm not
>>>really sure if probabilistic calculus is appropiate here, because chess games
>>>are not stocastic events.
>>>  So, I suggest an experiment to mesure the probabilistic noise:
>>>
>>>  -chose a random program and make it play itself.
>>>  -write down the result after 10 games, 50 games, 100 games...
>>>
>>>  It should tend to be an even result, and it would be possible to know how many
>>>games are needed to get a result with a certain degree of confidence.
>>>  If we try this for several programs, and the results are similar, we can draw
>>>a conclusion, in comparison with pure probabilistic calculus.
>>>
>>>  Does this idea make sense, or am I still sleeping? :)
>>>
>>>  José C.
>>
>>It is statistically invalid.  IE if you flip a coin 500 times do you _really_
>>expect to get 250 heads and 250 tails?  Probability distribution says you
>>won't get that very often at all.  In fact, if you flip long enough, you will
>>either get 500 straight heads or tails, or else prove the coin is _not_ actually
>>perfectly random with  50-50 probability of getting a head or tail.
>
>  But don't you think the more times you flip the coin, the closer the number of
>head and tails (in %) will be? Maybe the coin is not the better comparison, as
>it is a random event, and a chess game is not, but I still think it should work.
>But I expect a different rate of "closeness" (is this word correct?) for the
>same number of tries with the coin (random event) and the games (partially
>random -book, pondering, ... and partially not -eval function, search algos...),
>and that difference is what I want to measure.
>
>  José C.


No I don't.  Suppose that 500-0 run comes _first_.  How long will you have to
flip to get back to even?  You may _never_ get back to even.  Remember this is
a bell-curve shaped probability distribution.  Not a single spike on the curve
at the mid-point of the distribution.  You probably need to play 40 forty-game
matches to get the beginning of an idea of who is better.



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