Originally Posted by

**tableplay**
There is a very common metric used in statistics called the coefficient of variation. It's the standard deviation divided by the mean (sd/mean) and it is a very good measure of dispersion since it normalizes the standard deviation. Well guess what, Nzero is nothing more than the square of this very commonly used metric. That is, Nzero=CV^2=sd^2/mean^2. IMHO, below is a nice interpretation of Nzero. There is a massive body of statistical work about manufacturing processes and measures that express when a manufacturing process is in control or out of control, so that number of defects per units made estimation and minimization can be done. I guess in manufacturing, SCV, the square of the coefficient of variation (Nzero in Black Jack circles) would get a lot of interpretation and treatment as a metric, and this can probably be leveraged in AP circles to get a good handle on ROR for various casino games besides just black jack and that is where my interest in further reading stems from. So in a nutshell Nzero seems to be sparsely alluded to in gambling, but in reality it is very common in manufacturing and so there is actually a lot of stuff you can learn from it, by looking at the huge body of work about it in manufacturing and then hopefully applying it to AP stuff.

In the field of blackjack play, Don Schlesinger has done extensive work involving N0 (N-zero). It is covered extensively in his book,

*Blackjack Attack3*, which is one of the few books from several decades ago, that is still very pertinent to today's evolving game. Blackjack Attack 3 and my dear friend (sarcasm emoji) Qfit's software are the "must haves" for any serious blackjack player.

And by the way, admittedly, I don't understand all the formulas involved, or even that you just posted. I am not a math guy. I am very comfortable with using the math of those smarter than me.

So my simplified understanding of N0 as it relates to blackjack is that it is the number of trials necessary for results to overcome the short term variance that Alan and others seem to relish. It is where the math really begins to take over and we get to the long-term.

So when evaluating different games with different rules and conditions, we will have different N0's. Norm's software does this instantly and provides a N0. The higher that N0, the worse the game is.