Well, sample study we have looked at, this is really where you're trying to estimate the value of a parameter for a population. So what's an example of that? So let's say we take the population of people in a city, and so that could be hundreds of thousands of people, and the parameter that you care about is how much time, on average, do they spend on a computer. So the parameter would be for the entire population. If it was possible, you would go talk to every, maybe there's a million people in the city, you would talk to all million of those people, and ask them how much time they spend on a computer, and you would get the average, and then that would be the parameter. So population parameter, would be average time on a computer per day. Average daily time on a computer.