A Chemical Supply Company Currently Has in Stock 100lb of a Certain

Essay

A chemical supply company currently has in stock 100lb of a certain chemical, which it sells to customers in 5-lb lots. Let X = the number of lots ordered by a randomly chosen customer, and suppose that X has pmf $$\begin{array} { l r r r c } \hline x & 1 & 2 & 3 & 4 \\\hline P ( x ) & .2 & .3 & .3 & .2 \\\hline\end{array}$$ Compute E(X) and V(X). Then compute the expected number of pounds left after the next customer's order is shipped, and the variance of the number of pounds left. (Hint: The number of pounds left is a linear function of X.)