Sample standard deviation: stddev_samp

Syntax

• Aggregate syntax

in a Data Set expression	stddev_samp ( dataset { groupingClause } )
in a Component expression within an aggr clause	stddev_samp ( component ) { groupingClause }

• Analytic syntax

in a Data Set expression	stddev_samp ( dataset over ( analyticClause ) )
in a Component expression within a calc clause	stddev_samp ( component over ( analyticClause ) )

Input parameters

dataset	the operand Data Set
component	the operand Component
groupingClause	see Aggregate invocation
analyticClause	see Analytic invocation

Semantics for scalar operations

This operator cannot be applied to scalar values.

Input parameters type

dataset

dataset { measure<number> _+ }

component

component<number>

Result type

result

dataset { measure<number> _+ }
| component<number>

Additional Constraints

None.

Behaviour

The operator returns the “sample standard deviation” of the input values. For other details, see Aggregate and Analytic invocations.

Examples

Given the operand dataset DS_1:

Input DS_1 (see structure)

Id_1	Id_2	Id_3	Me_1
2011	A	XX	3
2011	A	YY	5
2011	B	YY	7
2012	A	XX	2
2012	B	YY	4

Example 1

DS_r := stddev_samp ( DS_1 group by Id_1 );

results in (see structure):

DS_r

Id_1	Me_1
2011	2.0
2012	1.414214