Question

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 hoper car loader is set to put 68 tons of coal into each car. The actual weights of coal loaded into each car are normally distributed, with mean = 68 tons and standard deviation = 1.2 ton.

What is the probability that 23 cars chosen at random will have a mean load weight x bar of less than 67.5 tons of coal? (Round your answer to four decimal places.)
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Answer 1

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 50 tons of coal into each car. The actual weights of coal loaded into each car are normally distributed, with mean = 50 tons and standard deviation = 0.9 ton.

(a) What is the probability that one car chosen at random will have less than 49.5 tons of coal? (Round your answer to four decimal places.)

(b) What is the probability that 35 cars chosen at random will have a mean load weight of less than 49.5 tons of coal? (Round your answer to four decimal places.)