Volcanoes almost every year, there is some incidence of volcanic activity on the island of japan. in 2005 there were 5 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 2-year period 2010–2011. 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?