Incidents Involving Serious Engine Problems on the DD-340 Aircraft Are

Multiple Choice

Incidents involving serious engine problems on the DD-340 aircraft are rare.They occur at an average rate of 3.0 per year (or .25 incidents per month) .Assume all Poisson conditions are met.Compute the average time, in months, between incidents.

A) 5.1
B) 6.2
C) 3.2
D) 4
E) 4.8