2) Past experience indicates that calls come to a switch board according to a Poisson Distribution with a mean rate of 6 calls every 2 minutes. a) Find the probability that 2 calls come in during a minute period. b) What is the probability that at least one call comes in during a minute period? c) Find the probability of one call during a 3-minutes period. d) What is the probability of exactly two call comes in during a minute given we had at least one call during a minute period