That's what I'm defining left as a successful trial, but could be right as well. Times the probability of 1 minus a successful trial, or non-successful trial. In this case, they're equally probable, and that's where I got the 2.5 from. And that's all in the spreadsheet. If you actually click on the cell and look at the actual formula, I did that. Although sometimes when you see it in Excel, it's a little bit confusing. And this is just the square root of that number, right?