Let x be the number of packages being mailed by a randomly selected customer at a certian shipping facility. suppose the distribution is x is as followsx | 1 2 3 4p(x) | .4 .3 .2 .1(a) consider a random sample of size n=2 (two customers), and let xbar be the sample mean number of packagesshipped. obtain the probability distribution of xbar.(b) use (a) to calculate p (xbar < = 2.) if a random sample of size 4 is selected, what is p (xbar < = 1.5)? (hint: don't list all possible outcomes; onlythose for which xbar < = 1.) find v(xbar)