And how much is due to variation from each data point to its mean? So let's figure out how much is due to variation between these guys over here. So one way to think about it, for each of these data points, actually, let's think about just this first group. For this first group, how much variation for each of these guys is due to the variation between this mean and the mean of means? Well, it's going to be, so for this first guy up here, I'll just write it all out explicitly, the variation is going to be its sample mean. So it's going to be 2 minus the mean of means squared. And then for this guy, it's going to be the same thing.