Statistics Meeting Book (May 15, 2019)

Reference: VIM, International Vocabulary of Metrology – Basic and general concepts and associated terms, 3 rd edition, JCGM 200: 2008 Expanded measurement uncertainty: product of a combined standard measurement uncertainty and a factor larger than the number one Notes: The factor depends upon the type of probability distribution of the output quantity in a measurement model and on the selected coverage probability. The term factor in this definition refers to a coverage factor. Expanded measurement uncertainty is also termed expanded uncertainty. Reference: VIM, International Vocabulary of Metrology – Basic and general concepts and associated terms, 3 rd edition, JCGM 200: 2008 Fitness for purpose: Degree to which data produced by a measurement process enables a user to make technically and administratively correct decisions for a stated purpose. Reference: Eurachem Guide: The fitness for purpose of analytical methods: A laboratory guide to method validation and related topics, 1998 HorRat: The ratio of the reproducibility relative standard deviation to that calculated from the Horwitz equation, Predicted relative standard deviation (PRSD)R =2C - 0.15 : HorRat(R) = RSDR/PRSDR , HorRat(r) = RSD r /PRSDR Where C is concentration expressed as a mass fraction (both numerator and denominator expressed in the same units). Notes: The HorRat is indicative of method performance for a large majority of methods in chemistry. Normal values lie between 0.5 and 2. (To check proper calculation of PRSDR, a C of 10 -6 should give a PRSDR of 16 %.) If applied to within-laboratory studies, the normal range of HorRat(r) is 0.3-1.3.