fejlmål

Fejlmål is a Danish term used to describe the measure of error in a measurement, referring to the deviation between a measured value and the true value. It is used to quantify accuracy and can be expressed as an absolute error or a relative error.

Etymology and usage: The word combines feil (fault, error) and mål (measure). In metrology, statistics, and quality control, fejlmål denotes the magnitude of discrepancy between what is observed and what is true, and it underpins the evaluation of measurement reliability.

Types and related concepts: The most common forms are absolute fejlmål, E_abs = |M − T|, where M is the measured value and T the true value; and relative fejlmål, E_rel = |M − T| / |T|, often given as a percentage. Distinctions are made between systematic error (bias) and random error, with measurement uncertainty providing a probabilistic range for the true value.

Calculation example: If the true value T is 120 units and the measurement M is 125, the absolute fejlmål is 5 units, and the relative fejlmål is 5/120 ≈ 0.0417, or about 4.17%. Note that when T is near zero, relative error can become large or ill-defined.

Uses and significance: Fejlmål is used in instrument calibration, quality control, data reporting, and experimental analysis to assess performance, set tolerances, and improve measurement methods by reducing errors.

See also: measurement error, uncertainty, accuracy, precision, calibration.