1. Definitions

1.1 Measurement result. Uncertainty

The purpose of measurement is to estimate the true value of a quantity A (e.g. the concentration of an element in a solution). The measurement is generally carried out on a quantity B of a different nature from A (light intensity, electrical signal, etc.) and produces a result y. Calibration makes it possible to estimate the relationship between the values of the two quantities and, therefore, to assign to A a value x deduced from the experimental result y.

These operations may be subject to errors due, for example, to imperfections in the equipment...