Standard Deviation and Confidence Intervals

[weevil]

In the process of building a new bankroll, I've logged 7k hands at 2/4 in the last week. My standard deviation is 18.6BB/100, and my BB/100 is at 8.5 (yeah, I've been running pretty well, even admist two, thousand + breakeven spells, these games are just damn soft). Obviously, something is incorrect with my standard deviation, since it would seem to imply I should have larger negative swings as well (I've only had one 100 hand session > -25BB, most losing sessions average around 4-5BB/100). Using a link I found in one of the forums for figuring your true BB/100 with a certain confidence interval, it thus appears there's a 95% chance I'm between 4.14 and 12.85BB/100 winner. I don't know the math behind these calculations, but they seem rather crazy, especially given that my strd/dev shouldn't be that high given that most of the deviation is in the positive.

To conclude, this isn't a brag post, but I am curious if I can have any confidence from these numbers and stats in being at least a 4BB/100 winner in the party 2/4 games? If so, since I can log 200 hands/hour easily, that's over $30/hour without rakeback, and a hell of a lot more than I can expect to earn in any current prospective job. Please don't repond with sarcastic illusions to my deity [img]/images/graemlins/tongue.gif[/img], helpful comments on the relavance of this sample size given the confidence interval calcuations involved is what I'm curious about.