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Subject: Re: Logistical questions

Author: Roger D Davis

Date: 19:25:02 12/26/00

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On December 26, 2000 at 22:24:00, Roger D Davis wrote:

>On December 26, 2000 at 14:28:15, Bruce Moreland wrote:
>
>>On December 26, 2000 at 09:59:45, Uri Blass wrote:
>>
>>>It seems that there are more draws between humans.
>>>
>>>If you look at the match between kramnik and kasparov there were 13 draws out of
>>>15.
>>>
>>>If you assume probability of 25% for the winner,5% for the loser and 70% draws
>>>then the standard deviation is smaller and you need less games to get
>>>significant result.
>>
>>If the draw percentage is 70%, you are right.  75 points should win that one out
>>about 87% of the time.
>>
>>But Kasparov should have been about to get 7.5 out of 15.0 93% of the time, and
>>win it outright 82% of the time.
>>
>>How many did he get, 6.5?  He should have gotten that score 0.5% of the time.
>>
>>But I don't think you can assume these huge draw percentages are "normal"
>>either.  GM games are usually in some larger context.  They achieve a winning
>>advantage in a match or tournament, then force draws to maintain this margin.
>>
>>>Another point is that the games are not independent events.
>>
>>Yes, I'm sure this messes everything up, but note that I'm not arguing for
>>statistical accuracy when choosing champions, either.
>>
>>I think it's more powerful for *us* if we apply it to computer chess, where
>>there is much less match strategy.
>>
>>bruce
>>
>>
>>>The first match between kasparov and karpov demonstrated it when karpov was
>>>leading 5-0 and decided to quit the match when he was leading 5-3 because he was
>>>tired.
>>>
>>>The reason that he decided to quit is that he knew that he was tired and that
>>>kasparov has bettter chances if the match continues.
>>>
>>>Karpov did not think about the games as independent events(otherwise he could
>>>prefer to continue and be almost sure of winning even if kasparov is slightly
>>>better).
>>>
>>>Even if you assume that the probability for kasparov to win a game is 0.2 and
>>>the probability of karpov to win a game is 0.1(I ignored white and black for
>>>doing the problem more simple) karpov had probability of 19/27 to win but karpov
>>>understood that the situation is worse than that and starting a new match from
>>>0-0 result is better for him.
>>>
>>>Uri
>
>Another problem for your argument is that ELOs are based on play across a pool
>of players. Match play is often (but not always) much different.
>
>If the two players reached some arbitrary large number of games with no
>statistical difference between the results, then there would simply be no
>statistically-significant champion, only a match winner. The fact that the
>winner is awarded the title of champion does not void the fact that there is no
>statistically significant difference between the two players, no matter how much
>you might like it to. What is at stake is simply whether the statistical
>equality of the two players is recognized (my point), or whether it remains
>obscure (your position).
>
>Roger


The "your argument" is addressed to Bruce, not to Uri.

Roger



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