Question

At a restaurant 80% of the users pay using credit cards. Find the probability that in a randomly selected sample of 5 users, exactly 2 users pay using credit cards.

Answer 1

This is a binomial distribution with n=5, p=0.8.

$P(X=2)=C_5^20.8^2(1-0.8)^{5-2}=0.0512.$