And the reason why it's reasonable to assume that it's a normal distribution is because it's a biological process. It's going to be the sum of many thousands and millions of random events. And things that are sums of many millions and thousands of random events tend to be normal distribution. So this is a population distribution. This is the population distribution. And we don't know anything really about it outside of the sample that we have here. Now, what we can do is, and this tends to be a good thing to do when you do have a sample, is just figure out everything that you can figure out about that sample from the get go.