In a recent year, potentially dangerous commercial aircraft incidents (e.g., near collisions) averaged 1.2 per 100,000 flying hours. Let X be the number of incidents in a 100,000-hour period.
(a) Justify the use of the Poisson model.
(b) What is the probability of at least one incident?
(c) More than three incidents?
(d) Construct the probability distribution (Excel or Appendix B) and make a graph of its PDF.