Question

Consider a binomial experiment with n=5 and p=0.20

What is p(x≥2)?

Answer 1

P(X = x) = nCx * p^x * (1 - p)^{n - x}

P(X > 2) = 1 - P(X < 2)

              = 1 - (P(X = 0) + P(X = 1))

               = 1 - (5C0 * (0.2)^0 * (0.8)^5 + 5C1 * (0.2)^1 * (0.8)^4)

                = 1 - 0.7373

                = 0.2627