To solve this question, we first need to realize that the expected number of phone calls in an 8-hour day is λ = 2 × 8 = 16. Using the Poisson distribution, we solve for the probability that X will be 20.
P(X = x) = (λ
xe
-λ) / x!
P(X = 20) = (16
20e
-16) / 20! = 0.0559 = 5.59%
