
BGonline.org Forums
Iancho PR Ranking February 2014
Posted By: Matt CohnGeier
Date: Monday, 3 February 2014, at 10:40 p.m.
In Response To: Iancho PR Ranking February 2014 (Stick)
If you win 50% of your matches, then the standard deviation of 100 matches is 5 matches either way. So 3 standard deviations is 15 matches, or the difference between winning 65% of your matches or 35% of your matches due to random luck.
After 1,000 matches the standard deviation is only 15 matches. That means 2 standard deviations on each side are a range from 47% to 53%, and 3 standard deviations on each side are a range from 45.5% to 54.5%.
Since most players will take over 10 years to play 1,000 matches, it is not really a very accurate assessment. However it is the best metric in the long run, and just because there is a sizable margin of error it doesn't mean it should be ignored. For example if your true longrun winning percentage is close to 65%, it is much easier to win several tournaments than if your true longrun winning percentage is close to 35%.
If you play lots and lots of matches or money games you will also reach a significant result more quickly, but since most people (and results tracking) are limited by number of tournaments they can attend in a year, statistically significant results are hard to accumulate.

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