And then last but not least, you have this data point where the residual is going to be the actual when x is equal to two is two minus the predicted. Well, when x is equal to two, you have 2.5 times two, which is equal to five minus two is equal to three. So two minus three is equal to negative one. And so when your actual is below your regression line, you're going to have a negative residual. So this is going to be negative one right over there. Now we can calculate the standard deviation of the residuals. We're going to take this first residual, which is 0.5, and we're going to square it.