Question

The number of lost bags per flight at Ango Airport follows a Poisson distribution with population mean. What is the probability that at least 2bags will be lost in a randomly selected flight?

Answer 1

Let $X=$ the number of lost bags per flight: $X\sim Po(\lambda)$

Given $\lambda=0.4$

$$P(X\geq 2)=1-P(X=0)-P(X=1)$$

$$=1-\dfrac{e^{-\lambda}\cdot\lambda^0}{0!}-\dfrac{e^{-\lambda}\cdot\lambda^1}{1!}$$

$$=1-\dfrac{e^{-0.4}\cdot0.4^0}{0!}-\dfrac{e^{-0.4}\cdot0.4^1}{1!}$$

$$=0.061552$$