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 86 tons of coal into each car. The actual weights of coal loaded into each car are normally distributed, with mean μ = 86 tons and standard deviation σ = 0.8 ton.
(a) What is the probability that one car chosen at
random will have less than 85.5 tons of coal? (Round your answer to
four decimal places.)
(b) What is the probability that 21 cars chosen at random
will have a mean load weight x of less than 85.5 tons of
coal? (Round your answer to four decimal
places.)
(c) Suppose the weight of coal in one car was less than
85.5 tons. Would that fact make you suspect that the loader had
slipped out of adjustment?
-Yes
-No
Suppose the weight of coal in 21 cars selected at random
had an average x of less than 85.5 tons. Would that fact
make you suspect that the loader had slipped out of adjustment?
Why?
-Yes, the probability that this deviation is random is very small.
-Yes, the probability that this deviation is random is very large.
-No, the probability that this deviation is random is very small.
-No, the probability that this deviation is random is very large.
Get Answers For Free
Most questions answered within 1 hours.