And from that, we're subtracting the sample variance, or I guess you could call this some kind of pseudo-sample variance, if we somehow knew the population mean. This isn't something that you see a lot in statistics, but it's a gauge of how much we are underestimating our sample variance, given that we don't have the true population mean at our disposal. And so this is the distance we're calculating. And you see we are always underestimating. Here, we overestimate a little bit, and we also underestimate. But when you take the mean, and when you average them all out, it converges to the actual value. So here, we're dividing by n minus 1.