SOLUTION: The mean weight of loads of coal placed in train cars by a loading machine is 43.0 tons with a standard deviation of 8.0 tons. Assuming that the weight of loads placed in the train

Question 655726: The mean weight of loads of coal placed in train cars by a loading machine is 43.0 tons with a standard deviation of 8.0 tons. Assuming that the weight of loads placed in the train cars by this loader are normally distributed, if a random sample of 9 loads is chosen for a weight check, find the probability that the mean weight of those loads is more than 40.60 tons.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
The mean weight of loads of coal placed in train cars by a loading machine is 43.0 tons with a standard deviation of 8.0 tons. Assuming that the weight of loads placed in the train cars by this loader are normally distributed, if a random sample of 9 loads is chosen for a weight check, find the probability that the mean weight of those loads is more than 40.60 tons.
--------
mean of the sample means: 43 tons
std of the sample means: 8/sqrt(9) = 8/3
------
t(40.6) = (40.6-43)/(8/3) = -0.9
----
P(x-bar > 40.6) = P(t > -0.9 when df = 8) = tcdf(-0.9,100,8) = 0.8028
=================
Cheers,
Stan H.
==============

RELATED QUESTIONS
Coal is carried from a mine in West Virginia to a power plant in New York in hopper cars... (answered by ikleyn)

Coal is carried from a mine in West Virginia to a power plant in New York in hopper cars... (answered by ikleyn)

Coal is carried from a mine in West Virginia to a power plant in New York in hopper cars... (answered by CPhill)

The mean weight of loads of brick is 46.0 tons with a standard deviation of 8 tons. 25... (answered by stanbon)

A freight train with 80 cars transports coal and iron ore. Each car carries either 100... (answered by richwmiller)

Please help me solve this question, thank you! The mean weight of loads of rock is... (answered by Theo)

Please help me solve this problem. Thank you! The mean weight of loads of rock is (answered by ikleyn)

Coal is carried from a mine in West Virginia to a power plant in New York in hopper cars... (answered by Boreal)

the mean weight of trucks traveling on a particular section of a highway is not known. A... (answered by stanbon)