Standard Deviation in Heads Up play

[Steve]

Would the standard deviation (of your win/loss per session) be higher in a Holdem ring game w/ 10 players, or a heads up match?

Obviously in the ring game you will win many fewer hands, roughly 1 out of 10, and those wins will be bigger pots. So that would seem to indicate the stddev would be bigger for the ring game, since you could very easily go a long time without winning a hand.

But in the heads up match, you are entering the pot more often, bluffing and calling bluffs more often, and dealing more hands per hour. So that would indicate its stddev would be higher.