The number of customers arriving at an ATM is in accordance with the Poisson distribution, with a mean rate of 1 customer in every 10 mins. What is the probability that there will be atleast 2 customers in half an hour??
Solution: Acc. to Poisson distribution, $\text{Mean}=\lambda=\frac{1}{10}$ $\mathbb{P}(X\geq{2})=1-\mathbb{P}(X=0)-\mathbb{P}(X=1)$ Is this the correct way, then how to calculate for 30 mins????