SOLUTION: The Montana Construction Supply Company makes PVC pipe that must withstand certain bending pressures. A sample item is taken every 2 minutes from this stable process, and 50 such i
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Question 1192818: The Montana Construction Supply Company makes PVC pipe that must withstand certain bending pressures. A sample item is taken every 2 minutes from this stable process, and 50 such items yield a sample mean of 32.1 pounds. Assume that an earlier study concluded that the standard deviation is 2.4 pounds. How large should a sample be if we want a 95% confidence interval for the mean with a margin of error of no more than 1.2 pounds? Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! error=z(0.975)*sigma/sqrt(n)
1.2=1.96*2.4/sqrt(n)
square both sides
1.44=3.8416*5.76/n
n=15.37 or 16
