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Subject: Re: Anand FIDE World Champion: Anand-Shirov 3,5-0,5

Author: Uri Blass

Date: 08:55:51 12/25/00

Go up one level in this thread


On December 25, 2000 at 10:08:44, Amir Ban wrote:

>On December 24, 2000 at 13:11:49, Christophe Theron wrote:
>
>>On December 24, 2000 at 09:09:27, Jeroen Noomen wrote:
>>
>>>My congratulations to Vishy Anand, for winning the
>>>FIDE World Championship 2000!
>>>
>>>3,5-0,5 in the final against Shirov, that leaves no
>>>discussion whatsoever. Anand was the best, remained
>>>unbeaten and scored a clear victory in the final.
>>>Well done!
>>>
>>>Jeroen
>>
>>
>>I am still absolutely amazed that a World Championship can be decided this way.
>>
>>A score of 3.5-0.5 is not statistically significant, not even with a low
>>confidence.
>>
>>It is now clear, at least amongst the experienced computers chess operators,
>>that such a result means NOTHING.
>>
>>I think that the computer chess community is on some topics much more advanced
>>than the human chess community. For example the human chess community has
>>adopted the ELO rating system, but still ignores most of the basic rules of this
>>system (margin of error, level of confidence). The computer chess community is
>>aware of these rules, and you can find these parameters published in the SSDF
>>rating list for example.
>>
>>
>>
>>    Christophe
>
>Chess games are not random events.
>
>You failed to do the math: 3.5-0.5 *is* significant, with about 95% confidence.

I do not know how do you get the 95% confidence.

You should define the assumptions that you make in order to find if it is
significant with 95% confidence.

There is also a problem in deciding if the result is significant.

If you do a small change in the program then 7-0 result can be not significant
from your point of view.

7-0 is very rare result between equal players but if you know that the change in
the program is small before testing then the probability that the weaker side
won 7-0 when you know that one side won 7-0 is not small enough.

Let assume that the probability for the weaker side to win a game is 0.3 when
the probability for the stronger side to win a game is 0.35

the probability of the weaker side to win 7 games when you know that one side
won is 0.3^7/(0.3^7+0.35^7)=0.2536... and it means that there is a probability
of more than 25% that you did a bad change inspite of the 7-0 result

I ignored the fact that the probability of white is not the same as the
probability of black to do it more simple.
>
>I noticed another statistic which *is* significant: It's always the bad results
>that are not significant. The good ones are accepted without question.
>
>Amir

A good result for one side is a bad result for the second side so if the bad
results are not significant then it also means that the good results are not
significant.

Uri



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