A certain grocery store sells four different kinds of milk: whole, 2%, 1%, and skim. The price of whole milk is $3.40 per gallon, the price of 2% milk is $3.25 per gallon, the price of 1% milk is $3.20 per gallon, and the price of skim milk is $3.10 per gallon. Let X1, X2, X3 and X4 be the total number of gallons of whole, 2%, 1%, and skim milk purchased during a particular week, respectively. Assume that X, X2, X3 and X are independent, and that 165, 425, 43 360, 44 = F each random variable is normally distributed, with = 300, 2 0125, 02 = 40, 03 20 and 04 30. = T - (a) (2 points) Define a random variable Y which represents the weekly revenue from the sale of milk. (b) (4 points) Find E(Y). (Write it to two decimal places.) (c) (4 points) Find the standard deviation of Y. (Round to the nearest integer.) (d) (4 points) Compute the probability that the weekly revenue from the sale of milk is at least $4,000. (Round to three decimal places.)