2) The average number annual trips per family to amusement park in the United States is Poisson distributed, with a mean of 0.6 trips per year. What is the probability of randomly selecting an American family and finding that:

a) The family did not make a trip to an amusement park last year?

b) The family took one trip to an amusement park last year?

c) The family took exactly four trips to an amusement park during three years period?

d) The family took at most one trips given the family took at least one trip to an amusement park last year?