# Computer Chess Club Archives

## Messages

### Subject: Re: A question about statistics...

Author: Ricardo Gibert

Date: 16:56:12 01/04/04

Go up one level in this thread

```On January 04, 2004 at 19:51:15, Peter Berger wrote:

>On January 04, 2004 at 19:46:51, Ricardo Gibert wrote:
>
>>On January 04, 2004 at 17:44:08, Dieter Buerssner wrote:
>>
>>>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.
>>
>>??? Not exactly the same thing at all. He said, "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 implies that +55-45=0 is the same as +10-0=90
>>and I completely disagree with this.
>>
>
>Dieter wasn't that wrong. My answer was non-sequitur and worded in a superficial
>way, which is a bad thing. Though you are right and my post made little sense I
>didn't really disagree with you anyway.

Okay, I understand what happened now. Thanks for clearing things up.

```