You may need to use the appropriate appendix table or technology to answer this question. During the period of time that a local university takes phone-in registrations, calls come in at the rate of one every four minutes. You can assume that calls arrive in a pattern following the Poisson distribution. (a) What is the expected number of calls in one hour? :1 (b) What is the probability of three calls in ve minutes? (Round your answer to four decimal places.) :1 (c) What is the probability of no calls in a five-minute period? (Round your answer to four decimal places.) :1