# segregation variance of increment collection

**S**,_{s}^{2}__n__the variance caused by nonrandom distribution of ash content or other constituent in the lot. For a method of estimating this variance, see Annex A1 of Test Methods D2234/D2234M.**D2234/D2234M**

*ASTM D121-09a Standard Terminology of Coal and Coke.
2014.*

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**variance**— n the mean square of deviations (or errors) of a set of observations; the sum of squared deviations (or errors) of individual observations with respect to their arithmetic mean divided by the number of observations less one (degrees of freedom);… … Coke&Coal Terminology