Volcanoes Almost every year, there is some incidence of volcanic activity on the island of Japan. In 2005, there were five volcanic episodes, defined as either eruptions or sizable seismic activity. Suppose the mean number of episodes is 2.4 per year. Let X be the number of episodes in the two-year period 2013–2014.

a) What model might you use to model X?

b) What is the mean number of episodes in this period?

c) What is the probability that there will be no episodes in this period?

d) What is the probability that there are more than three episodes in this period?

e) How much activity would convince you that there is a significant increase in volcanic activity in the region?