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"}]}