An actuary determines that the numbers of major earthquake in certain area follows Poisson distribution with mean 2 per year. 1. whart is the probability that the inter-arrival time of two major earthquakes is less than three months? 2. what is the probability that there will be no major earthquakes in a year? 3. counting the number of no major earthquake years in the next 10 years, what is the probability that the count is two. 4. counting the number of no major earthquake years in the next 100 years, what is the probability that the count is over 15. 題目如上述，是否可請各位大大幫忙解題，小弟一直苦無頭緒，也不知如何下筆。 看起來是卜瓦松過程，但還是不知要如何解題，也不太清楚題意，是否可以請各位 賜教，謝謝!! -- --

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