And there are some fairly sophisticated ways of coming up with this 10% threshold. People could have picked 9%. They could have picked 10.1%. But 10% is a nice round number. And if we look at some tangible examples, it seems to do a pretty good job. So for example, right over here, let's let x be the number of boys from three trials of selecting from a classroom of n students where 50% of the class is a boy and 50% of the class is a girl. And so what we have over here is we have a bunch of different n's.