We have observed the New York Subway systems and found on Saturdays, three (3) trains will arrive in an hour if there are no delays. Assume no delays for the next few questions

a) What probability distribution function is indicated by subway arrivals? Explain why.

b) What is the probability that no (0) trains will show up in an hour?

c) What is the probability, as you observe for an hour, that at least 6 trains arrive?

d) What is the probability, as you observe for an hour, that less than 4 trains arrive?

e) What is the probability between 3 and 7 trains arrive, inclusive (3 and 7 are included)?