And it's also called r squared. You might have even heard that term when people talk about regression. Now, let's think about it. If the standard, if the squared error of the line, if the squared error is really small, if the squared error is really small, what does that mean? It means that these errors, it means that these errors right over here are really small, are really small, which means that the line is a really good fit. Which means that the line, this line over here, it tells us that the line is a really good fit. So if the, let me write it over here.