Author: Rolf Tueschen
Date: 09:00:01 01/23/04
Go up one level in this thread
On January 23, 2004 at 11:26:42, Bob Durrett wrote: >On January 23, 2004 at 10:12:00, Rolf Tueschen wrote: > >>We just had a little dispute about an old topic. When can we say that a prog is >>better than another? How can we proceed to make sound arguments? >> >>Let me tell the story in fast mode. >> >>There was a test. I understand with 300 games or such. An incredibly high number >>of games because often we have matches with onl 20 or 40 games. >> >>I understood further that on the base of a confidence intervall of 1-58 we have >>95%. >> >>Now what I want to tell you, and this is undisputable statistical standard: >> >>if you get a value that is in the intervall, we cannot conclude that the >>difference of the two progs is relevant or valid or call it what you want. It >>makes no sense to argue with such "low" differences. They could be still be on >>the base of chance. Now the distribution of chance is the Bell curve. Nothing >>else. >> >>We had the debate with the SSDF list often enough. >> >>Two progs stand at the top. One is number one in the ranking. But is it really >>stronger than prog number two??? >> >>The answer is easy. If the normal variation, this famous +- value in the SSDF >>list is say +-40 points and the difference between progs is 35 points THEN we >>are unable to conclude anything for sure. It could be that 1 is stronger than 2 >>but also the contrary could be true. Only from values >40 on we have >>"certainty", statistically, that a prog in that specific design is proven >>stronger than another one. >> >>This is all so simply and trivial that it is satifying to be able to clarify. >> >>Have fun, >> >>Rolf >> >>P.S. >> >>I just want to correct a heavy mistake in a former posting. There it was said >>for Elo differences that the difference of say 1 Elo point would be speaking for >>a better strength of one prog over another and you needed so and so many gasmes >>to prove that... - - this is total nonsense. There is _no_ way to conclude >>anything out of an Elo difference of 1 point, no matter if you have 300 or >>100000 games. The difference of 1 Elo point is meaningless. It's nonsense to >>even think about such neccessary millions of games to "prove" that. Statistics >>also has something to do with normal human sense. We would always take such a >>difference for _equal_ strength. > >I enjoyed reading your bulletin, Rolf. : ) Unfortunately I admit not >comprehending properly, but that is probably my oncoming senility. Of course, >if you do not comprehend the following then you will have to admit to the >possibility of your oncoming senility too! : ) : ) > >I often say to people: "There are no guarantees in this life." This could be >paraphrased to "There is nothing absolutely certain in life." [I do not wish to >discuss religion.] My point is that statistics is a helpful tool in man's >pursuits but not absolute. I see statistics as being useful in several ways. >First, it helps in the pursuit of making some sense out of a mess of data. >Secondly, it provides a convenient way to express our expectations, providing >such exotic terminology as "confidence," and the like. > >I see a tournament as being a tool too. It helps us to improve our odds of >being on the right path. If we seek to determine who [or what] is best, who is >second best, etc., then statistics provides us with useful tools to improve our >chances of "getting it right." But there is no guarantee. > >It appears absolutely true that every tournament provides some information. The >problem is in identifying that information, measuring it, and finding a good way >to express or communicate that new information. > >This forum seems to have a problem coming to grips with the idea that there is >useful information in every tournament. People seem "hung up" on the mandate to >determine a "winner." That causes all kinds of misunderstandings. > >Well, so much for my "brilliant gems of wisdom." I'll try to do better next >time. : ) > >Bob D. Really, what you wrote seems to me much clearer than what I've written myself! That must be folie a deux then. :) :) :) Rolf
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