And so that's equal to 5. That's where that number comes from. And then the variance, and I'm not sure if I went over this. 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.