Answer:
1 call
Step-by-step explanation:
The expected number of calls, or the mean number of calls (E(X)), is given by the sum of products of each possible outcome by their respective likelihoods.
Since all of the events have the same likelihood (1/3), the mean number of calls is:
[tex]E(X) = \frac{1}{3}*(0+1+2)\\X=1[/tex]
The mean number of calls in a five-minute period is 1 call.