Portland cement is packed in bags of nominal weight 80 pounds. The actual mean weight of a bag is found to be 80.2 pounds with a coefficient of variation of 1.2%. A normal distribution applies....

Portland cement is packed in bags of nominal weight 80 pounds. The actual mean weight of a bag is found to be 80.2 pounds with a coefficient of variation of 1.2%. A normal distribution applies. Railway flat cars are loaded with enough bags to make up anominalload of 60 tons on each car. A train is made up of fifty flat cars.

a) What is the mean weight of a car load?

b) What is the standard deviation of the weight of a car load?

c) What are the 95% confidence limits for the weight of a train load of Portland cement?