Now, what is the mean of our y's? The mean of our y's, once again I'm going to do this in a neutral color, the mean of our y's is equal to 2 plus 1 plus 3, all of that over 3. So this is 2 plus 1 is 3 plus 3 is 6 divided by 3 is equal to 2. This is 6 divided by 3 is equal to 2. Now, what is the mean of our xy's? Well, over here, it's going to be, so our first xy over here is 1 times 2 plus 2 times 1 plus 4 times 3. And we have 3 of these xy's, so divided by 3.