Imprecision of measurements

Analytical ranges and imprecision of measurement in a typical blood gas and electrolyte analyzer... 

Precision may be defined as the closeness of agreement between independent results of measurements obtained under stipulated conditions.The degree of precision is usually expressed on the basis of statistical measures of imprecision, such as the SD or CV (CV = SD/x, where x is the measurement concentration), which thus is inversely related to precision. Imprecision of measurements is solely related to the random error of measurements and has. no relation to the trueness, of measurements. 

The advances in sample fractionation methods, sample derivatization approaches, and the instrumentation of GC and GC/MS, in particular, are fundamental to metabolic profile research. Biological variation that is inherent to the samples of physiological fluids or tissues should not be obscured by an excessive imprecision of measurement techniques. Thus, reliable sampling and sample treatment procedures (including as much automation as is feasible) should precede the use of sophisticated GC and GC/MS techniques. 

The intraindividual variations of AChE and BuChE activities (CV = 6-9%) are. significantly. smaller than the inter-individual variations and arc similar to variations reported for the day-to-day imprecision of measurements (Abemethy etai, 1988 Brock, 1990 Flcgar-Mc tric era/., 1999). 

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See also in sourсe #XX -- [ , ]

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