This problem deals with the number of events occurring within a fixed period with a known average value, so we use the Poisson distribution. In Excel, we apply the function POISSON.DIST(x, λ, cumulative), where
𝑥
x (read: x) is the number of occurrences,
𝜆
λ (read: lambda) is the mean, and the cumulative argument determines the type of probability calculated. Specifically, FALSE is used to compute the probability of exactly
𝑥
x, written as
𝑃
(
𝑋
=
𝑥
)
P(X=x) (read: P of X equals x), wh