Standard deviation is low when the values in the sample are all close together. If you want a small standard deviation, you would avoid all big pots. Big wins and losses are outliers from the average, the further from the average the greater the effect. (You can't avoid small pots, since most pots are folded pre-flop, winning 0 bb/100)
Originally Posted by jyms
Or does this stdev only include VPIP hands? Either way, you want the amount you win to be as close to the same (your average) every time as possible for a low std dev. Of course, eliminating as many negative values from the set will help, too (losses are BAD), since your average is hopefully positive.
stdev = sqrt( sum( ( x - mu )^2 )/( n - 1 ) )
x is each individual value in the data sample
mu is the mean (average) value of the sample
n is the number of data elements in the sample