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Subject: Re: I'm wrong about 10-0 vs 60-40

Author: Andrew Dados

Date: 23:55:44 02/01/01

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On February 01, 2001 at 10:21:43, Uri Blass wrote:

>On February 01, 2001 at 07:39:11, Leen Ammeraal wrote:
>
>>On January 31, 2001 at 20:17:17, Bruce Moreland wrote:
>>
>>>I expressed very forcefully that a 10-0 result was more valid than a 60-40
>>>result.
>>>
>>>I've done some experimental tests and it appears that I'm wrong.
>>>
>>>I have no idea why.
>>>
>>>bruce
>>
>>According to the little Windows app Whoisbetter by Steve Maugham,
>>the certainty of being better for the winner is
>>97% with the score 60 - 40, and
>>99% with the score  7 -  0
>
>It is clearly wrong.
>The probablities that you talk about are not the probability that the winner is
>better.
>
>We cannot know the probability that the winner is better unless we have more
>knowledge.

We can calculate this and if we disregard draws the chance that winner of 60-40
is better is indeed 97.4%. If we count-in draws to the model, then at 50% chance
of draw between equal players (see my post above) the above number goes up to
99.6% (!).

How can you calculate this: for each possible rating difference calculate
probability of 60-40 score then normalize factorial of that to 1 (100%).

-Andrew-

>
>97% and 99% is what is called by statistics the level of confidence and the name
>level of confidence is misleading.
>
>You can be sure in 99% that the result betwenn *EQUAL* players is not 7-0 for
>one of them.
>
>Pay attention that we talk about *EQUAL* players and not about a case when one
>is stronger.
>
>
>Uri



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