a) the rate of occurrence is constant, does not change based on time. The probability of an event occurring is proportional to the length of the time period.
b) 2*60 = 120
c) P(x;u) = e^-u u^x/x!
u = 4.
compute probabilities for x = 1, 2 and 3 and sum probabilities
d) u = 6
compute probabilities for x = 0 and 1, sum probabilities then subtract from 1
e) u = 2, compute probability for x = 0