Guide to the Expression of Uncertainty

ISO (1993) Guide to the expression of uncertainty in measurement. ISBN 92-67-10188-9, ist Edn., Geneva, Switzerland. 

Ingamells CO, PiTARD FF (1986) Applied Geochemical Analysis, pp L-84.Wiley, New York. International Federation of Clinical Chemistry (IFCC) (1978) Expert Panel on Nomenclature and Principles of Quality Control in Clinical Chemistry. Clin Chim Acta 83 L89F-202F. International Organization for Standardization (ISO) (1993) Guide to the expression of uncertainty. Geneva. 

The proper application of the ISO Guide to the expression of uncertainty in measurement requires that aU sources of rmcertainty are included. In practical terms this means an uncertainty budget has to be developed also by the user. The development of an rmcertainty budget, and the consequences for both analysts and producers is described later in Section 7.2. 

ANSI and NCSL, U.S. Guide to the Expression of Uncertainty in Measurement, 1800 30 Str., Suite 305B, Boulder, CO 80301, USA, ANSI/NCSLZ540-2-1997, (1997). 

The Guide to the Expression of Uncertainty in Measurement (GUM) to some extent is the Bible of uncertainty estimation. Since it was originally made for physical measurements in metrology laboratories, it is quite difficult to translate it into analytical chemistry problems, especially for routine measurements. 

However, the GUM [Guide to the Expression of Uncertainty of Measurement approach (ISO 1993a), which leads to the verbose statement concerning expanded uncertainty quoted above, might not have been followed, and all the analyst wants to to do is say something about the standard deviation of replicates. The best that can be done is to say what fraction of the confidence intervals of repeated experiments will contain the population mean. The confidence interval in terms of the population parameters is calculated as... 

The approach to measurement uncertainty that is espoused by many authorities, including the VIM, is embodied in a standard called the Guide to the Expression of Uncertainty in Measurement, universally referred to as... 

The definition of metrological traceability (see above) stipulates that each link in the chain has a known uncertainty. Nowadays, this concept and its application have been reformulated by the BIPM and recently detailed in the Guide to the expression of uncertainty in measurement (GUM) [26] parameter, associated with the result of a measurement, that characterizes the dispersion of the values that could reasonably be attributed to the measurand . Useful explanations are provided in several other guides [26-30] as well as commentaries [e.g. 31-33], The philosophy is to apply a bot-tom-up approach by formulating a function of all input quantities giving the measurand as output. An uncertainty budget of all sources of uncertainty is established. Important items to consider are ... 

According to the Vocabulary in Metrology (VIM) [2] and the Guide to the Expression of Uncertainty in Metrology (GUM) [3] measurement traceability is defined as... 

In the IMEP programme1, Si-traceable values with a full measurement uncertainty according to the Guide to the expression of uncertainty in measurement (GUM) are disseminated by IRMM to field (and other) laboratories by means of appropriately prepared test samples. The uncertainties are the end-product of an evaluation process of all uncertainty sources which is as complete as... 

The expanded uncertainty U is obtained by multiplying crx by an appropriate coverage factor (k) as specified in the Guide to the expression of Uncertainty in Measurements (GUM). Thus U=kax and X. U. 

Guide to the Expression of Uncertainty in Measurement, ISBN 92-67-10188-9, International Organization for Standardization, Geneve 1993, orders at http //www.iso.ch/infoe/other-pub.html Metrology and measurement... 

International Organization for Standardization, Guide to the Expression of Uncertainty in Measurement, Geneva, 1995. 

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