*Choose Index below for a list of all words and phrases defined in this glossary.*

**Variance (v or Σ )** - The mean of the squared deviations of a set of values, expressed as :

[Category=Data Quality ]

*Source: Larry English, http://www.iaidq.com/main/glossary.shtml , 14-Feb-2009 11:30 *

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**Variance** - The sum of the squared deviations of n measurements from their mean divided by (n-1).

The deviation from what was expected.

Deviation from process mean ie, away from the target which often results in extra cost to revert back on target/mean.

[Category=Data Quality ]

*Source: iSixSigma, 03 March 2011 09:09:55, http://www.isixsigma.com/index.php?option=com_glossary *

**Variance (statistical) **- A measure or dispersion of a sample or population distribution.

[Category=Quality Assurance ]

/;/Source: Massachusetts Department of Environmental Protection, 29 March 2011 08:59:36, http://www.mass.gov/dep/cleanup/laws/glossa01.htm //

**variance **- [statistics] A numeric description of how values in a distribution vary or deviate from the mean. The larger the variance, the greater the dispersion of values around the mean. The standard deviation for a distribution is the square root of the variance.

[Category=Geospatial ]

*Source: esri, 25 September 2012 08:33:36, http://support.esri.com/en/knowledgebase/GISDictionary/term/abbreviation *

Data Quality Glossary. A free resource from GRC Data Intelligence. For comments, questions or feedback: dqglossary@grcdi.nl