measurement result

The outcome of an analytical measurement (application of the chemical measurement process), or value attributed to a measurand. This may be the result of direct observation, but more commonly it is given as a statistical estimate derived from a set of observations. The distribution of such estimates (estimator distribution) characterizes the chemical measurement process, in contrast to a particular estimate, which constitutes an experimental result. Additional characteristics become evident if we represent as follows: The true value, , is the value that would result if the chemical measurement process were error-free. The error, , is the difference between an observed (estimated) value and the true value; i.e. (signed quantity). The total error generally has two components, bias () and random error (), as indicated above. The limiting mean, , is the asymptotic value or population mean of the distribution that characterizes the measured quantity; the value that is approached as the number of observations approaches infinity. Modern statistical terminology labels this quantity the expectation value or expected value, . The bias, , is the difference between the limiting mean and the true value; i.e. (signed quantity). The random error, , is the difference between an observed value and the limiting mean; i.e. (signed quantity).