George flips an unfair coin 7 times. The coin has a 1/4 probability of coming up heads and a 3/4 probability of coming up tails. What is the probability that he flips exactly 2 tails?
This is a binomial probability problem.......the probability is given by :
C (7, 2) * ( 1/4)^5 (3/4)^2 = 189 / 16384 ≈ .0115 ≈ 1.15%
