Assume that n = 9, and p = [ 5/7]. Find the probability of at least 2 successes and at least 2 failures.

If s = success and f = failure, the possibilities are:

s = 2 and f = 7     P = 9C2 x (5/7)^2 x (2/7)^7

s = 3 and f = 6     P = 9C3 x (5/7)^3 x (2/7)^6

s = 4 and f = 5     P = 9C4 x (5/7)^4 x (2/7)^5

s = 5 and f = 4     P = 9C5 x (5/7)^5 x (2/7)^4

s = 6 and f = 3     P = 9C6 x (5/7)^6 x (2/7)^3

s = 7 and f = 2     P = 9C7 x (5/7)^7 x (2/7)^2

Find each of the above probabilities and add them together for the total probability.