Author: Peter Fendrich
Date: 17:55:33 01/04/04
Go up one level in this thread
On January 04, 2004 at 17:44:08, Dieter Buerssner wrote: >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? I don't know how Elostat is working but it should be close to: s=SQRT(W(1-m)^2 + D(0.5-m)^2 + L(0-m)^2/(n-1)) A=1.96 * s/SQRT(n) where s is estimated standard deviation n is number of games m is score/n W,D,L is number of Wins, Draws and Losses respectivelly A is the margin of error (for score, not rating points) 1.96 is fethed from the Normal Distribution table to get 95% reliability SQRT is the square root Now we have an 95% interval of scores from m-A to m+A Compute the ratings for m-A and m+A and that's it. Finally I think that you guys should download http://remi.coulom.free.fr/WhoIsBest.zip and read about why draws doesn't count when finding out who is best. (That's something else than computing ratings where draws definitely counts) /Peter
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