Customers arrive at bakery at an average of 10 customers per hour. What is the probability that less than 5 customers will arrive in the next hour? Assume Poisson arrivals. a. .0378 b. .0293 c. .2500 d .1126 Solution Possion Distribution PMF of P.D is = f ( k ) = e- x / x! Where = parameter of the distribution. x = is the number of independent trials P( X < 5) = P(X=4) + P(X=3) + P(X=2) + P(X=1) + P(X=0) = e^-10 * 0 ^ 4 / 4! + e^-10 * ^ 3 / 3! + e^-10 * ^ 2 / 2! + e^-10 * ^ 1 / 1! + e^-10 * ^ 0 / 0! = 0.0293 P(less than 5 customers will arrive in the next hour) = 0.0293.