精度管理の考え方中　恵一

ばらつき dispersion

測定値の大きさがそろっていないこと、または不ぞろいの程度、バラツキの大きさを表すには、標準偏差などを用いる（Z8402）。

　ISO/DIS 17511では、　uncertainty of measurement　が次のように定義されている。
　parameter, associated with the result of a measurement, that characterizes the dispersion of the values that could reasonably be attributed to the measurand; the parameter can be, for example, a standard deviation (or a given multiple of it), or the half-width of an interval having a stated level of confidence; the components of uncertainty are evaluated experimentally from statistical distributions (Type A) or evaluated from assumed probability distributions based on experience or other information (Type B). All components are expressed as standard uncertainties that are combined into one final expression.