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 89 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 89 tons of coal into each car. The actual weights of coal loaded into each car arenormally distributed, with mean μ = 89 tons and standard deviation σ = 0.5 ton.

a) What is the probability that 35 cars chosen at random will have a mean load weight x of less than 88.5 tons of coal? (Round your answer to four decimal places.)

b) Suppose the weight of coal in 35 cars selected at random had an average x of less than 88.5 tons. Would that fact make you suspect that the loader had slipped out of adjustment? Why?