Let X be a Binomial random variable with parameters n; . Prove the

expectation and variance of X are n(pi) and n(1-pi) respectively. (Hint: use

the defi…nition of expectation and variance and the relation between Bernoulli

and Binomial.

So E(x) = sum(xP(x)) and Var(x) = sum((x-u)^2*P(x))

Not really sure where to go from here. P(x) for binomial is equal to n!/x!(n-x)!*pi^x*(1-pi)^(n-x)