Question 1113611: An ethanol railroad tariff is a fee charged for shipments of ethanol on public railroads. An agricultural association publishes tariff rates for railroad-car shipments of ethanol. Assuming that the standard deviation of such tariff rates is $1100, determine the probability that the mean tariff rate of 250 randomly selected railroad-car shipments of ethanol will be within $100 of the mean tariff rate of all railroad-car shipments of ethanol. Interpret your answer in terms of sampling error.
The probability is __. (Round to three decimal places.)
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! An ethanol railroad tariff is a fee charged for shipments of ethanol on public railroads. An agricultural association publishes tariff rates for railroad-car shipments of ethanol.
Assuming that the standard deviation of such tariff rates is $1100, determine the probability that the mean tariff rate of 250 randomly selected railroad-car shipments of ethanol will be within $100 of the mean tariff rate of all railroad-car shipments of ethanol. Interpret your answer in terms of sampling error.
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Find the z-value of the sample rates $100 below and $100 above the mean
of the sample means.
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lower z value = -100/(1100/sqrt(250)) = -1.4374
upper z value = +1.4374
Ans: prob = normalcdf(-1.4374,1.4374) = 0.849
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Cheers,
Stan H.
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