The number of arrivals at a customer information desk is 2 per minute. Assuming the number of arrivals follows a poisson distribution, find (a) the expected number of arrivals in 3 minutes and (b) the variance of the number of enquiries arriving in 3 minutes.
Attempt:
(a) \begin{equation} E(x=2) = 2 \times 3 = 6 \end{equation} is this correct for part (a)?
I am not sure how to start with part (b) - any suggestions would be greatly appreciated!