stats question

5. Throughout the day, customers arrive at a shop according to a Poisson process With rate A : 15 per hour. Let X denote the number of arrivals between 9am and 12noon, and let Y denote the number of arrivals between 9am and 4pm. (a 10pts) Are X and Y independent? Explain. (b lpts) Find Cov[X,Y). (c 10pts) Compute E(Y|X : 10). Justify