To test the quality of the work of a commercial laboratory, duplicate analyses of a purified benzoic acid (68.8% C, 4.953% H) sample were requested. It is assumed that the relative standard deviation of the method is sr →  = 4 ppt for carbon and 6 ppt for hydrogen. The means of the reported results are 68.5% C and 4.882% H. At the 95% confidence level, is there any indication of systematic error in either analysis?

To test the quality of the work of a commercial laboratory, duplicate analyses of a purified benzoic acid (68.8% C, 4.953% H) sample were requested. It is assumed that the relative standard deviation of the method is sr →  = 4 ppt for carbon and 6 ppt for hydrogen. The means of the reported results are 68.5% C and 4.882% H. At the 95% confidence level, is there any indication of systematic error in either analysis?

Principles of Instrumental Analysis

7th Edition

ISBN:9781305577213

Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Publisher:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Chapter11: Atomic Mass Spectrometry

Section: Chapter Questions

Problem 11.10QAP

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Question

To test the quality of the work of a commercial laboratory, duplicate analyses of a
purified benzoic acid (68.8% C, 4.953% H) sample were requested. It is assumed that the
relative standard deviation of the method is sr →  = 4 ppt for carbon and 6 ppt for
hydrogen. The means of the reported results are 68.5% C and 4.882% H. At the 95%
confidence level, is there any indication of systematic error in either analysis?

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