Question

          (ii) If 1% of an airline’s flight suffers a minor equipment failure in an aircraft, what is the probability that there will be exactly 5 such in the next 1000 such flights?                             

        

Answer 1

If we use the approximation of binomial distribution by Poisson, then:

$λ=np=0.01×(1000)=10.$

$P(X=5)=\dfrac{e^{-10}\cdot10^5}{5!}\approx0.0378.$