Suppose you have a line of chairs behind each other, at fixed distances from you, and one person sits on the chair in front. As time goes on, you keep on observing this person. For most of the time, he or she sits in the chair in front, but occasionally, after giving him or her let us say a snack or something, the person is ‘excited’ and goes to the chair behind it for a short time, after which he or she goes back to the first chair again. Very rarely, the person goes to one of the chairs that are even further away, but not for a very long time. If you observe this person for about 1 hour, and keep track of the amount of minutes he or she sits on each chair, you can say something about where the person sits most on average during that hour.