The daily number of arrivals of patients to an emergency room is a Poisson random variable with a mean of 144 patients per day. A day is 24 hours.
(i) Let X be the time between two patients' arrival, what is the distribution of X? [1].
(ii) What is the density function of X? [1]
(iii) It is 11:00 AM and a patient just arrived, what is the probability that the next patient will arrive by 11:10 AM? [2]
(iv) What is the expected value of Y = 2X + 5? [1]
(v) Use the normal approximation for the Poisson distribution to obtain the approximate probability that 156 or more people arrive in a day.