Question

On an average, a bus stops at a certain point every 15 minutes. Whats the probability that no bus will turn up in a single 15 minute interval?

Answer 1

Let $X=$ the number of buses: $X\sim Po(\lambda).$

Given $\lambda=1$.

$$P(X=0)=\dfrac{e^{-1}(1)^0}{0!}=\dfrac{1}{e}\approx0.36788$$