And so what I do, so the variance, and I will do, and this is a population variance that I'm talking about, just to be clear. It's a parameter. The population variance I'm going to denote with the Greek letter sigma, lowercase sigma. This is capital sigma. Lowercase sigma squared. And I'm going to say, well, I'm going to take the distance from each of these points to the mean. And just so I get a positive value, I'm going to square it.