Answer:
6.13% probability that in a randomly selected office hour, the number of student arrivals is 3.
Explanation:
In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:

In which
x is the number of sucesses
e = 2.71828 is the Euler number
is the mean in the given time interval.
A statistics professor finds that when he schedules an office hour for student help, an average of 1 students arrive.
This means that
.
Find the probability that in a randomly selected office hour, the number of student arrivals is 3.
This is P(X = 3). So


6.13% probability that in a randomly selected office hour, the number of student arrivals is 3.