This was the numerator. This right here is the numerator when we were trying to figure out the slope of the regression line. So we tried to figure out the slope of the regression line. Let me just rewrite the formula here just to remind you. It was literally the mean of the products of each of our data points, minus, or the XYs, minus the mean of Ys times the mean of the Xs. All of that over the mean of the X squareds, and you could even view it as this, over the mean of the X times the Xs, but I could just write the X squareds over here, minus the mean of X squared. This is how we figured out the slope of our regression line.