It's the more expansive definition of paradox, meaning something like "counterintuitive result". In expectancy, a randomly chosen person has an average number o

It's the more expansive definition of paradox, meaning something like "counterintuitive result". In expectancy, a randomly chosen person has an average number of friends. You might therefore think that a random person and their friends, all of whom seem randomly chosen, would have the same expected number of friends. But you'd be wrong, because the friends weren't random after all: they had at least one friend. Not a logical paradox, but a surprising fact.