You are developing a procedure for determining traces of copper materials using a wet digestion followed by measurement by atomic absorption spectrophotometry. In order to test the validity of the method, you obtain an NIST orchard leaves standard reference material and analyze this material. Five replicas are sampled and analyzed, and the mean results are found to be 10.8 ppm with a standard deviation of plus or minus 0.7. ppm. The listed value for the standard reference is 11.7 ppm. Does your method give a statistically correct value at the 95% confidence level?

You are developing a procedure for determining traces of copper materials using a wet digestion followed by measurement by atomic absorption spectrophotometry. In order to test the validity of the method, you obtain an NIST orchard leaves standard reference material and analyze this material. Five replicas are sampled and analyzed, and the mean results are found to be 10.8 ppm with a standard deviation of plus or minus 0.7. ppm. The listed value for the standard reference is 11.7 ppm. Does your method give a statistically correct value at the 95% confidence level?

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter8: Sampling, Standardization, And Calibration

Section: Chapter Questions

Problem 8.27QAP

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You are developing a procedure for determining traces of copper in biological materials using a wet digestion followed by measurements by atomic absorption spectrophotometry. In order to test the validity of the method, you obtain a NIST orchard leaves standard reference material and analyze this material with your procedure five times and obtain a mean of 12.27 ppm with a standard deviation of 0.097 ppm. The NIST sample is listed as 11.7 ppm. Does your method give a statistically valid value at the 95% confidence level?
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