Question 2:

2. 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 7'5 tons of coal into each car. The actual weights of coal loaded into each car are normally distributed. with a mean of [1 = 7'5 tons and standard deviation of o = 1.210ns. (a) What is the probability that one car chosen at random will have less than 74.5 tons of coal? (b) What is the probability that 36 cars chosen at random will have a mean load weight a? of less than 74.5 tons of coal? (:2) (.9 Suppose the weight of coal in one car was less than 74.5 tons. Would that fact make you suspect that the loader had slipped out of adjustment? Why? (:19 Suppose the weight of the coal in 36 cars selected at random had an average .1? of less than ?4.5 tons. Would the fact make you suspect that the loader had slipped out of adjustment? Why