So plus negative one squared. And then finally we have that fourth residual, which is 0.5 squared. 0.5 squared. So once again, we took each of the residuals, which you could view as the distance between the points and what the model would predict. We are squaring them. When you take a typical standard deviation, you're taking the distance between a point and the mean. Here we're taking the distance between a point and what the model would have predicted.