Question

Assume that the monthly worldwide average number of airplane crashes of commercial airlines is 2.2. What is the probability that there will be
(a) at least 3 such accidents in the next month?
(b) at most 5 such accidents in the next 2 months?
(c) exactly 7 such accidents in the next 4 months?

Answer 1

Monthly worldwide average number of airplane crashes of commercial airlines is 2.2.

That means that = 2.2 / months

Let X be the number of airplane crashes

X~ poisson ( = 2.2 / months )

a) P( X >= 3) = 1- P( X <=2 ) = 1- 0.62271 = 0.37729

b) For 2 months = 2.2* 2 / 2months = 4.4 per 2 months

P( X <=5 ) = 0.71991

( from the poisson table with  = 4.4 )

c) For 4 months = 2.2* 4 / 4months = 8.8 per 2 months

P( X = 7) = = = 0.1222