Question

Find the probability of exactly four successes in five trials of a binomial experiment in which the probability of success is 40%. Round to the nearest tenth of a percent.

Answer 1

p(4 successes) ≈ 7.7%

Explanation:

p(k successes in n trials) = C(n,k)·p^k·(1-p)^(n-k)

You have n=5, k=4, p=0.4, so the probability is ...

p(4 successes) = C(5,4)·(0.4)^4·(1 -0.4)^1 = 5·0.4^4·0.6 = 0.0768

p(4 successes) ≈ 7.7%