A safety engineer studying several decades of accidents at a facility notices that one particular type appears to happen either once in a month or not at all.The engineer also notices that there appears to be no distinct pattern of when the accidents happen nor any clustering of accidents and concludes that the events are (stochastically) independent. On average, there has been about 1 accident every four months.

Using the Poisson model, what is the chance that there are no accidents in the next year?