Or maybe you measure it in some way. And then you plot it all, you look at the data, and you see if those two variables move together. So what does that mean? Well, let me draw. So if this axis is, let's say this is computer time, computer time, and this axis is blood pressure. Blood pressure. So let's say that there's one person who doesn't spend a lot of time on a computer, and they have a relatively low blood pressure.