a statistics professor receives an average of five email mes

a statistics professor receives an average of five email messages per day from students. Assume the number of messages approximates a poisson distrivution. What is the probility that on a randomly selected day she will have four messages?

Solution

the probability that on a randomly selected day she will have four messages=

P(X=4) in a Poisson distribution with average = 5

= 0.1755