The sum of a series of observations divided by the number of observations. Symbol: x(bar). It can be calculated by the formula: \[\bar{x}=\frac{\sum x_{i}}{n}\]
Note:
All summations are taken from 1 to n. Note that the arithmetic mean is an unbiased estimate of the population mean, i.e. µ is the limiting value for x(bar), as n -> ∞.
Source:
PAC, 1994, 66, 595. 'Nomenclature for the presentation of results of chemical analysis (IUPAC Recommendations 1994)' on page 599 (https://doi.org/10.1351/pac199466030595)