So how can we figure that out? Well, there's several ways to do it. We know that this is the area above one standard deviation above the mean. You could use a z-table, or you could use some generally useful knowledge about normal distributions. And that's that the area between one standard deviation below the mean and one standard deviation above the mean, this area right over here, is roughly 68%. It's closer to 68.2%. For our purposes, 68 will work fine.