If a fair coin is tossed 9 times, what is the probability, to the nearest thousandth, of getting exactly 1 heads?
this is a binary problem ... heads or tails
(t + h)^9 = t^9 + 9 t^8 h + ... + h^9
the 2nd term is exactly one head ... p(one h in nine tosses) = 9 * (1/2)^9