Standard devation ques

I just went out and bought Blackjack Attack and a few of the Beat the X-Deck game books. My main question is on the second part of the chapter where Don explains standard devation. Suppose I know what my exact average bet will be for a certian number of hands how do I figure ount what my sd will be? I know that the regular formula is {1.1 * (sqrt)N} where N = number of hands played, but that doesn't seem to explain the sd numbers Snyder gave in his books. Also really stumped ove the sd per hand. Isn't the square root of 1 still 1? What am I missing here?

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