Chemistry 155 Introduction to Instrumental Analytical Chemistry
Chemistry 155 Introduction to Instrumental Analytical Chemistry
Chemistry 155 Introduction to Instrumental Analytical Chemistry
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Chem <strong>155</strong> Unit 1 Page 34 of 313See also, appendix a1C in Skoog, Holler and Nieman.But, be advised that there is a typo in older editions.Equation a1-32 should read:m = S XY /S XXAlso – it is a somewhat more subtle problem <strong>to</strong>calculate the error in a concentration determined froma calibration curve of signal (y) versus concentration(x).You will need <strong>to</strong> follow Skoog appendix-a calculations<strong>to</strong> deal with this problem in your lab reports whereyou determine an unknown concentration. M = thenumber of replicate analyses, N = the number of datapoints.Equation a1-37Skoog 5th edition.s cs y⋅m1M+1N+( ) 2yc avg− y avbm 2 ⋅S xxNote: when computing a confidence interval using thiss C value, the degrees of freedom are N-2. (See forexample Salter C., “Error Analysis Using theVariance-Covariance Matrix” J. Chem. Ed. 2000, 77,1239.Page 34 of 313
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