1. The problem statement, all variables and given/known data If I flip a fair coin n times, that is the probability that I get k heads? 2. Relevant equations nCk: the combination in which order doesn't matter s.t one picks k from n. 3. The attempt at a solution there are 2*2*2*2*2.....*2=2^n total outcomes. but the event specifies k ways of picking heads out of n flips. So, (nCk)/(2^(n)). Is this correct? Intuitively, I think its sound.