http://fr.wikipedia.org/wiki/Critères_de_dispersion

Après avoir déterminé où se situent les valeurs du caractère statistique en cherchant des critères de position, on peut chercher à déterminer la dispersion de ces valeurs.

Übrigens auch Streuung
http://dict.leo.org/frde?lp=frde&lang=de&searchLoc=0&cmpType...

http://en.wikipedia.org/wiki/Statistical_dispersion

Measures of statistical dispersion
A measure of statistical dispersion is a real number that is zero if all the data are identical, and increases as the data becomes more diverse. An important measure of dispersion is the standard deviation, which is the square root of the variance (which is itself a measure of dispersion).

Other such measures include the range, the interquartile range, the mean difference, and the average absolute deviation, and, in the case of categorical random variables, the discrete entropy. None of these can be negative; their least possible value is zero.

A measure of statistical dispersion is particularly useful if it is location-invariant, and linear in scale. So if a random variable X has a dispersion of SX then a linear transformation Y = aX + b for real a and b should have dispersion SY = |a|SX. One of the forms in which statistical variability is realized in the empirical sciences is that of differences in repeated measurements of the same quantity.


En mesure physique (métrologie), cette dispersion est estimée par l'écart type, qui sert à calculer l'erreur de mesure. De manière plus générale, il est important de savoir si les valeurs sont groupées ou au contraire dispersées, ce qui indique si la population est uniforme ou pas vis-à-vis du critère testé.