Question

During the period of time that a local university takes phone-in registrations, calls come in at the rate of one every two minutes.a. What is the expected number of calls in one hour?b. What is the probability of three calls in five minutes?c. What is the probability of no calls in a five-minute period?

Answer 1

Explanation:

This is a poisson distribution. Let x be a random representing the number of calls in a given time interval.

a) the expected number of calls in one hour is the same as the mean score in 60 minutes. Thus,

Mean score = 60/2 = 30 calls

b) The interval of interest is 5 minutes.

µ = 5/2 = 2.5

We want to determine P(x = 3)

Using the Poisson probability calculator,

P(x = 3) = 0.21

c) µ = 5/2 = 2.5

We want to determine P(x = 0)

Using the Poisson probability calculator,

P(x = 0) = 0.08