Created
April 29, 2015 14:32
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Standard deviation in (pure) SPARQL
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| SELECT ((SUM((?n - ?mean)*(?n - ?mean)))/(COUNT(?n) - 1) AS ?sdev) WHERE { | |
| ?obs qb:value ?n . | |
| { | |
| SELECT (AVG(?n) AS ?mean) WHERE { | |
| ?obs qb:value ?n . | |
| } | |
| } |
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This actually calculates variance, (including Bessel's correction). To go from this to a standard deviation requires a square root operation, which isn't available in pure SPARQL.