here’s a fascinating social experiment. select one hundred people at random in new york city and ask them each to list all their friends, so you can figure out their average number of friends. then, in turn, ask their friends how many friends they have. you will find that the latter’s average number of friends is higher. sociologist scott feld of purdue university drew attention to this apparent paradox. the explanation lies in the realization that there is a bias in the question being asked, since you are more likely to know popular people and less likely to know unpopular ones. that is also why people at your local gym tend to be fitter than you, because you do not encounter the relatively out­of­shape ones who rarely turn up.
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