And I really encourage you to play with this and explore the Excel formulas and everything. This area right here, between minus 1 and 1. Now one thing that shows up a lot is what's the probability that you land within the standard deviation of, and just so you know this graph, the central line right here, this is the mean, and then these two lines I drew right here, these are one standard deviation below and one standard deviation above the mean. And some people think, what's the probability that I land within one standard deviation of the mean? Well, that's easy to do. What I can do is I'll just click on this and I could call this, what's the probability that I land between, let's see, one standard deviation, the mean is minus 5, one standard deviation below the mean is minus 15. And one standard deviation above the mean is 10 plus minus 5 is 5.