And hopefully, it'll make a little bit more sense. Just so you know where we're going with this, the point of this is so that we can eventually do some inferential statistics about differences of means. How likely is a difference of means of two samples, random chance or not random chance? Or what is a confidence interval of the difference of means? That's what this is all building up to. So anyway, we know the mean of this distribution right over here. And what's the variance of this distribution?