Coal is carried from a mine in West Virginia to a power plant in New York in hopper cars on a long train. The automatic hopper car loader is set to put 81 tons of coal into each car. The actual...

Coal is carried from a mine in West Virginia to a power plant in New York in hopper cars on a long train. The automatic hopper car loader is set to put 81 tons of coal into each car. The actual weights of coal loaded into each car arenormally distributed, with mean ? = 81 tons and standard deviation ? = 1.6 ton.