what is the probability that a coin will be flipped six times, and have it land heads up twice?
+23251 This is a combinations problem: C(6,2)·(1/2)2·(1/2)4 = 15 / 64
A combination of 6 items taken two at a time (the two locations where the heads are found among the six possible places: C(6,2) = 15
... times the probability of getting 2 heads: (1/2)2
... and times the probability of getting four tails: (1/2)4.
