Computer Chess Club Archives




Subject: Re: A question about statistics...

Author: Dieter Buerssner

Date: 14:44:08 01/04/04

Go up one level in this thread

On January 04, 2004 at 13:46:48, Ricardo Gibert wrote:

>On January 04, 2004 at 12:47:25, Peter Berger wrote:
>>On January 04, 2004 at 12:40:00, Ricardo Gibert wrote:
>>>On January 04, 2004 at 12:29:15, Mark Young wrote:
>>>>A score of 17 - 3 in a 20 game match has a certainty of over 99% that the winner
>>>>of the match is stronger then the loser.
>>>>A 100 game match ending 55 - 45 only has a 81% chance that the winner of the
>>>>match is the stronger program.
>>>>A 200 game match ending 106 - 94 only has a 78 % chance that the winner is
>>>>stronger then the loser.
>>>Nothing you have said is really correct because you have ignored the significant
>>>effect of draws in a match.

I think, I understand the issue you rise. However, 17-3 will be more significant
than the other results independent of draw. So, still some truth there. I really
wonder, how exactly Elostat calculates the +/- margins to the calculated rating.
Does anybody know an URL, where one can read this?

>>The percentage of draws doesn't matter at all when it is about the conclusion
>>which program is strongest based on the above match results.
>>This has been shown by Remi Coloum and explained in multiple posts
>>here(unfortunately the search engine hasn't found a new home yet).
>>6-0 with 0 draws and 6-0 with 1000 draws has the exact same prediction value
>>when it is about the question which engine is stronger based on a match result.
>In this case, the number of decisive games (w+L=6) and margin of victory (w-L=6)
>is the same in both cases so the conclusion they have equal value is correct.
>    -------------------------------
>In the examples given before, the number of decisive games depends on the number
>of draws e.g. +17-3=0 and +14-0=6 are not of equal value since the number
>decisive games are not equal.

Hey, I think Peter and Ricardo wanted to say exactly the same thing. Still they
succeeded to disagree.


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