You would actually say, how many people are between 5.1 inches and 4.9 inches taller than the average? You have to give it a little bit of range, because no one is exactly, or it's almost infinitely impossible to the atom to be exactly 5' 9". Even the definition of an inch isn't defined that particularly. So that's how you use this function. I think this is so heavily used in, one, it shows up in nature, but in all of inferential statistics, I think it behooves you to become as familiar with this formula as possible. And I guess to make that happen, let me play around a little bit with this formula, just to kind of give you an intuition of how everything works out, et cetera, et cetera. So if I were to take this, and I like to just maybe help you memorize it, this could be rewritten as, if we take the sigma into the square root sign, if we take the standard deviation in there, it becomes 1 over the square root of 2 pi sigma squared.