And then the last one we have to calculate is the mean of the x squareds. So what's the mean of the x squareds? The first x squared is just going to be 1 squared, this 1 squared right over here, plus this 2 squared, plus 2 squared right over here, plus this 4 squared, plus this 4 squared. And we have 3 data points again. So this is 1 plus 4, which is 5, plus 16. 5 plus 16 is equal to 21 over 3, which is equal to 7. So that worked out to a pretty neat number.