Analytical Chem istry - DePauw University

202 Analytical Chemistry 2.0data set. All three standard deviations about the regression are 1.24,and all three data regression lines have a correlation coefficients of0.816. Based on these results for a linear regression analysis, commenton the similarity of the data sets.(b) Complete a linear regression analysis for each data set and verifythat the results from part (a) are correct. Construct a residual plotfor each data set. Do these plots change your conclusion from part(a)? Explain.(c) Plot each data set along with the regression line and comment onyour results.(d) Data set 3 appears to contain an outlier. Remove this apparentoutlier and reanalyze the data using a linear regression. Commenton your result.(e) Briefly comment on the importance of visually examining yourdata.13. Fanke and co-workers evaluated a standard additions method for a voltammetricdetermination of Tl. 16 A summary of their results is tabulatedin the following table.ppm TladdedInstrument Response (mA)0.000 2.53 2.50 2.70 2.63 2.70 2.80 2.520.387 8.42 7.96 8.54 8.18 7.70 8.34 7.981.851 29.65 28.70 29.05 28.30 29.20 29.95 28.955.734 84.8 85.6 86.0 85.2 84.2 86.4 87.8Use a weighted linear regression to determine the standardization relationshipfor this data.5JSolutions to Practice ExercisesPractice Exercise 5.1Substituting the sample’s absorbance into the calibration equation andsolving for C A giveS samp = 0.114 = 29.59 M –1 × C A + 0.015C A = 3.35 × 10 -3 MFor the one-point standardization, we first solve for k A16 Franke, J. P.; de Zeeuw, R. A.; Hakkert, R. Anal. Chem. 1978, 50, 1374–1380.