Pat and sam are arguing about the probability of obtaining 2 heads and 2 tails in 4 flips of a fair coin, in that specific order. pat says, "the probability equals 1/16, since there is one way this outcome can occur, and the experiment has 16 different possible outcomes". sam says "the probability equals 6/16, since the corresponding entry in row 4 of pascal's triangle is 6, and the sum of the entries in that row equals 16." who is correct, and why?