EMUE-D3-4-SoilContaminantsMeasurement

The example describes the evaluation of measurement uncertainty for the routine determination of acidextractable toxic metals in soil using a combination of acid extraction and atomic emission spectrometry. The example illustrates the general approach to measurement uncertainty evaluation taken by ISO 21748, which uses information on precision and trueness of a routine test procedure to provide an indication of the measurement uncertainty to be expected from the procedure. The example further illustrates the experimental determination of sensitivity coefficients that cannot readily be derived from a mathematical model, examines the evaluation of uncertainties arising from calibration using straight-line regression with zero intercept, and discusses the issues arising in the event of an appreciable bias which is not corrected for when within permitted limits. The zip files contained in the dataset are: LaTeX: this contains a zip of the files needed to generate the stand-alone example from Latex, with no data or R code. R Markdown: this contains another zipped set, including all of the source files and data that generate the example. All the statistical analysis code is embedded in the .rmd file in that zip set. Data: this contains a separate (but otherwise identical) copy of the data used by the R code in the markdown file. All of the data files are tab-delimited plain text format. The header for each file contains a description of the data in the file; the header is marked as comment lines using #.