Please explain standard deviation. I googled it, looked it up in the dictionary, yet still cannot implement it into blackjack calculation. When reviewing simulations in a blackjack program I purchased there is a section that shows the standard deviation of the simulations I ran (SD#1, SD#2, SD#3). Is this what could be won or lost? How much bankroll fluctuates while the allotted time of hands are played? And why is there 3 different levels of it?

Thanks for any info related to this matter. These are the questions you'll get from a "ditch digger" trying to learn math again twenty years after leaving high school a bit too early without that favorable diploma...