A fair Coin is tossed times. Let be the absolute difference in the number of
heads and tails obtained. Then the probability distribution is given by

where . The most probable value of is , and the expectation value is

**References**

Handelsman, M. B. Solution to Problem 436, ``Distributing `Heads' Minus `Tails.''' *College Math. J.* **22**,
444-446, 1991.

© 1996-9

1999-05-25