They could have negative values. But since we're squaring and taking the sum of squares, this is always going to be positive. And the place that this is going to be useful, and we're going to see in the next few videos, is in measuring essentially error from an expected value. And if you take this total error, you can figure out the probability of getting that total error if you hold some parameters, or if you assume some parameters. And we'll talk more about it in the next video. Now with that said, I just want to show you how to read a chi squared distribution table. So if I were to ask you if this is our distribution, let me pick this blue one right here.