VAR_q

Updated 2023-10-24 14:54:50.327000

Syntax

SELECT [westclintech].[wct].[VAR_q] (
   <@Values_RangeQuery, nvarchar(4000),>)

Description

Use VAR_q to estimate variance based on a sample. To estimate the population variance from a sample of N elements with an unknown mean (the mean being calculated from the sample itself):

\frac{1}{N-1}\sum_{j=0}^{N-1}(x_j-\bar{x})^2 

Arguments

@Values_RangeQuery

the select statement, as text, used to determine the values used in the VAR_q function.

Return Type

float

Remarks

If you want measure the population variance, then use the VARP_q function.

For simpler queries or for queries on de-normalized data, use the VAR function.

No GROUP BY is required for this function even though it produces aggregated results.

Examples

CREATE TABLE #k1

(

    [num] [float] NOT NULL

);

INSERT INTO #k1

VALUES

(91.3698);

INSERT INTO #k1

VALUES

(76.3382);

INSERT INTO #k1

VALUES

(74.5692);

INSERT INTO #k1

VALUES

(85.2957);

INSERT INTO #k1

VALUES

(99.0112);

INSERT INTO #k1

VALUES

(86.99);

INSERT INTO #k1

VALUES

(70.7837);

INSERT INTO #k1

VALUES

(72.834);

INSERT INTO #k1

VALUES

(78.1644);

INSERT INTO #k1

VALUES

(77.7472);

INSERT INTO #k1

VALUES

(66.0627);

INSERT INTO #k1

VALUES

(59.781);

INSERT INTO #k1

VALUES

(68.4793);

INSERT INTO #k1

VALUES

(78.6103);

INSERT INTO #k1

VALUES

(59.8621);

select wct.VAR_q('SELECT num from #k1');

This produces the following result.

{"columns":[{"field":"column 1","headerClass":"ag-right-aligned-header","cellClass":"ag-right-aligned-cell"}],"rows":[{"column 1":"121.668645804095"}]}