I’m going to use a friend’s stats who just happens to have played 50000 rounds of poker.
$1/$2NL mostly on Party and Empire. ev $9/100 and sd is $126/100. Does not include bonuses.
After 500 hrs of play we would expect our player to be up $4500, and his sd for that period to be sqrt of 500 x $126.00. So sd would be $2818. Let’s assume he broke even. Then he would be 4500/2818 or 1.6 sd’s down from expectation.
Using the normal distr table. 1.6 sd’s equals .05 or a 1 in 20 shot of flat earnings. This is hardly a lightening strike. Now some of you will have better numbers and some will have worse numbers, but this will at least give you an idea of what you can expect. I suggest if you who want to understand this further go to 2 + 2 and do some searches.