Question

An unfair coin with a probability of tails as 0.55 is tossed 8 times. Find the probability that a tail shows up more than 2 times.

Answer 1

0.9115

Explanation:

Using a binomial probability function :

P(x =x) = nCx * p^x * (1 - p)^(n - r)

Probability of success, p = 0.55

1 - p = 1 - 0.55 = 0.45

n = 8

x = 2

P(x > 2 ) = p(x = 3) + p(x = 4) + p(x = 5) + p(x = 6) + p(x = 7) + p(x =8)

To save computation time, we could use the binomial probability calculator :

P(x > 2 ) = 0.9115