And so what we want to do, if we say zero is right over, if we said that zero is right over here on our distribution, so that is D is equal to zero, we want to figure out, well what is the area under the curve less than that? So we want to figure out this entire area. There's a couple of ways you could do this. You could figure out the z-score for D equaling zero, and that's pretty straightforward. You could just say this z is equal to zero minus our mean of eight divided by our standard deviation of 10. So it's negative eight over 10, which is equal to negative 8 1⁄10. So you could look up a z-table and say, what is the total area under the curve below z is equal to negative 0.8?