8.1 Estimation Using Normal

# The paper is expected to have a mean length of 11

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Unformatted text preview: roduction process to change the length of the paper produced. You select a random sample of 100 sheets, and the mean paper length is 10.998 inches. Construct a 95% and a 99% confidence interval estimate for the population mean paper length. Comment on the functioning of the At 95% confidence level, zα/2 = z.025 = 1.960 production process. Interval estimate: x ± zα 2 σn .02 10.998 ±1.960 0100 10.998 ± 0.00392 10.99408 ≤ µ ≤11.00192 With 95% confidence, we conclude that the population mean is between 10.99 and 11.00 inches. The desired mean is within this interval and we can conclude the production process is working Example 1 Interval Estimation A paper manufacturer has a production process that operates continuously throughout an entire production shift. The paper is expected to have a mean length of 11 inches, and the standard deviation of the length is 0.02 inches. At periodic intervals, a sample is selected to determine whether the mean paper length is still equal to 11 inches or whether something has gone wrong with the production process to change the length of the paper produced. You select a random sample of 100 sheets, and the mean paper length is 10.998 inches. Construct a 95% and a 99% confidence interval estimate for the population mean paper length. Comment on the functioning of the For α=0.05 production process. using CONFIDENCE.NORM(alpha,standard_dev,size) lower: =10.998– CONFIDENCE.NORM(0.05,0.02,100)=10.99408007 upper: =10.998+CONFIDENCE.NORM(0.05,0.02,100)=11.00191993 Therefore, we are 95% confident that the population mean is between 10.9941 and 11.0019 and the process is working correctly. Example 1 Interval Estimation A paper manufacturer has a production process that operates continuously throughout an entire production shift. The paper is expected to have a mean length of 11 inches, and the standard deviation of the length is 0.02 inches. At periodic intervals, a sample is selected to determine whether the mean paper length is still equal to 11 inches or whether something has gone wrong with the production process to change the length of the...
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## This document was uploaded on 03/05/2014.

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