I need to prove this to you if I have. And I'll make a whole other video on the variance of the binomial distribution. But the variance is essentially equal to the number of trials, 10, times the probability of taking the left step, or kind of a successful trial. 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.