Keskimääräinen

Keskimääräinen is a Finnish adjective meaning average or mean. It is used to describe quantities that represent the central tendency of a data set and can refer to both everyday notions of typical value and formal statistical concepts. The related noun keskiarvo denotes the arithmetic mean itself; keskimääräinen describes a property of having an average value, as in keskimääräinen pituus or keskimääräinen arvo.

Etymology: Keskimääräinen is formed from keskimäärä, meaning the average amount, with the suffix -inen to produce an adjective. Keskimäärä itself derives from keskus (center, middle) and määrä (amount). The word reflects the idea of a central, typical value in a set of numbers.

Usage: In statistics, keskimääräinen is used to indicate the arithmetic mean, especially in phrases such as keskimääräinen arvo or keskimääräinen luku. It is distinct from mediaani (median) and moodi (mode). In everyday language, it is common to refer to an average value, for example keskimääräinen palkka (average salary).

Calculation: For a data set x1, x2, ..., xn, the keskimääräinen arvo, i.e., the keskiarvo, equals (x1 + x2 + ... + xn) / n. A weighted average, or painotettu keskiarvo, is computed as sum(wi*xi) / sum(wi). Different averaging methods highlight different aspects of the data and have varying sensitivity to outliers.

See also: keskiarvo, mediaani, moodi, tilastotiede.