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Old 10-21-2007, 11:56 AM
AaronBrown AaronBrown is offline
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Join Date: May 2005
Location: New York
Posts: 2,260
Default Re: Variance is Fractal

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You cant get a truthful picture of the "variance" of a thing unless you have the mean to that thing.

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That depends entirely on the relative size of the mean and standard deviation. An error of 1% on the mean causes an error of 1% of the mean on the standard deviation. If the mean is small compared to the standard deviation (say on a one-day stock return), this is a trivial error and you can estimate the variance far more accurately than the mean. If the mean is large compared to the standard deviation (say on heights of healthy adult males), this is a large effect.

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If you do not document wins/losses and keep stats then you have no way of calculating your mean, variance or EV (unless you are annette_15).

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I half agree. You don't have to document anything, but you do have to keep some statistics. You don't need to record every hand result, but you should keep at least open, high, low and close bankrolls per session. I know of no way to compute poker win parameters without data.

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(fixed variance) example: The mean (long run) win rate for AA vs KK HU seeing all 5 cards is 83%. A measured sample over say 200 games of a win rate of 72% is variance. The more sessions, or iterations the closer you get to the true "mean" of that thing. The mean is the truth of an equation. In this example the mean was the win rate of AA vs KK HU while seeing all five cards.

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Actually, AA beats KK 1,399,204 out of 1,712,304 times, for 81.7%. It also ties 7,923 times which gives equity (tie counts as half win) of 82.2%.

In this example, the mean (82.2%) is high compared to the standard deviation (37.8%). If you measure a 72% win rate for AA, you will estimate a 44.9% standard deviation. Your 14% error on the mean will correspond to a 41% error on the variance.

But this is only because you postulate a mean higher than the standard deviation. Suppose you measured the KK win rate instead of the AA win rate. Now your error on the mean is 57% (you measured 28% instead of the correct 17.8%). So now the error on the mean is larger than the error on the variance.

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There is (fixed) variance (odds), and there is variance of your theoretical "edge" (dynamic) and tilt (dynamic).... By using solid bankroll management, variance will rarely have you lifting an eyebrow unless you've been on tilt.

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I agree the first sentence is a reasonable way to analyze edge. The second is a matter of preference. If you play poker to grow your bankroll, it often makes sense to take risk with it. Poker without bankroll risk is called "penny ante." It's a fun game for kids and people who hate risk.

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It often makes the hair on the back of your neck stand on end with or without tilt!

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This seems to be the opposite of what you said above. If it's true for you, I suggest you shave your neck to get rid of the tell.
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