Excerpted from Bogle on Mutual Funds by John C. Bogle, page 163

It is interesting, if not entirely fair, to compare the mutual fund performance derby that attracts so much press attention to a coin-flipping contest. In the contest, 100 persons begin slipping coins; at the end of ten flips, the most likely outcome is that 25 persons will have flipped five heads and five tails. The chances are virtually nil that anyone will flip either all heads or all tails. The upper chart illustrates the pattern of the expected outcome of the coin-flipping contest. The lower chart illustrates the actual outcome of the contest among equity fund managers for performance over the ten years ended December 31, 1992. The 100 largest growth and value fund managers had average annual gross returns of +15.6%. The table shows that 28 provided returns between +15% and +16%, 17 provided returns between +16% and +17%, and 21 provided returns between +14% and +15%, and so on. Three of the 100 managers defied the averages, as it were, two by earning returns of more than +20%, and one by earning a return of less than +11%. As you can see, the patterns are remarkably similar. A winning coin flipper commands no press interest; a winning fund manager is acclaimed a near genius.