CONFIDENCE

Updated 2023-11-02 21:18:54.500000

Syntax

SELECT [westclintech].[wct].[CONFIDENCE] (
  <@Alpha, float,>
 ,<@Standard_dev, float,>
 ,<@Size, float,>)

Description

Use the scalar function CONFIDENCE to calculate a value that you can use to construct a confidence interval for a population mean. Confidence intervals are used to indicate the reliability of an estimate.

Arguments

@Alpha

is the significance level use to compute the confidence interval. The confidence interval equals 1- @Alpha. @Alpha is an expression of type float or of a type that can be implicitly converted to float.

@Size

is the sample size. @Size is an expression of type float or of a type that can be implicitly converted to float.

@Standard_dev

is the population standard deviation for the dataset. @Standard_dev is an expression of type float or of a type that can be implicitly converted to float.

Return Type

float

Remarks

If @Alpha = 0 or @Alpha= 1, CONFIDENCE returns an error.

If @Standard_dev = 0, CONFIDENCE returns an error.

@Size is truncated to zero decimal places.

If @Size < 1, CONFIDENCE returns an error.

CONFIDENCE = NORMSINV(1-@Alpha/2)*(@Standard_dev/SQRT(@Size)).

Examples

select wct.CONFIDENCE(.025, 6.25, 150);

This produces the following result.

{"columns":[{"field":"column 1","headerClass":"ag-right-aligned-header","cellClass":"ag-right-aligned-cell"}],"rows":[{"column 1":"1.14381103915062"}]}

select wct.NORMSINV(.9875) * (6.25 / SQRT(150));

This produces the following result.

{"columns":[{"field":"column 1","headerClass":"ag-right-aligned-header","cellClass":"ag-right-aligned-cell"}],"rows":[{"column 1":"1.14381103915062"}]}