I agree with Nynefingers. The standard deviation is calculated easily enough from the data on the Wizard's site on the distribution of payoffs. The variance for one hand and a one-unit wager is 24.28469, and the standard deviation is 4.92795. This assumes one-unit wagers on the ante AND on the blind (with the rules requiring equal bets on those two spots). The problem can be defined differently, by specifying a half-unit wager on each spot, and obviously the answer will be different in that case. This also assumes perfect basic strategy, which is not reasonably achievable by human players. The expectation from perfect basic strategy is -2.19%. The expectation from a simplified basic strategy will be in the neighborhood of -2.35%, and the standard deviation will differ slightly from the figure given above, but I don't know in what direction.