Let X be the number of packages being mailed by a randomly selected customer at a certain shipping facility. Suppose the distribution of X is as follows: x 1 2 3 4 p(x) .4 .3 .2 .1 Consider a random sample of size n=2 (two customers) and let X be the sample mean number of packages shipped. Obtain the probability distribution of X . Calculate expected value of the sample mean E(X ). Calculate variance of the sample mean, V(X ). Calculate standard deviation of the sample mean (Standard Error of the Mean), _X ..