In an experiment to monitor two calls, the PMF of N, the number of voice calls, is
![1965_5b5b17c3-3bfb-4f14-9eab-e93c36915c7d.png](https://secure.tutorsglobe.com/CMSImages/1965_5b5b17c3-3bfb-4f14-9eab-e93c36915c7d.png)
(a) Find E[N], the expected number of voice calls.
(b) Find E[N2], the second moment of N.
(c) Find Var[N], the variance of N.
(d) Find σN , the standard deviation of N.