# CFLib.org – Common Function Library Project

## VarianceSamp(values)

##### Last updated September 07, 2001

Version: 1 | Requires: CF5 | Library: MathLib

Description:
Returns the sample variance for a set of numeric values. Variance is a measure of how spread out a distribution of data is. This method is used when you have values representing a population sample.

Return Values:
Returns a numeric value.

Example:

``````<CFSET Values="1,2,3,4,5,6,7,8,9,10">

<CFOUTPUT>
Given <CFIF IsArray(Values)>{#ArrayToList(Values)#}<CFELSE>{#Values#}</CFIF><BR>
The variance for the sample is #VarianceSamp(values)#
</CFOUTPUT>
``````

Parameters:

Name Description Required
values Comma delimited list or one dimensional array of numeric values. Yes

Full UDF Source:

``````/**
* Returns the sample variance for a set of numeric values.
*
* @param values      Comma delimited list or one dimensional array of numeric values.
* @return Returns a numeric value.
* @author Rob Brooks-Bilson (rbils@amkor.com)
* @version 1.0, September 7, 2001
*/
function VarianceSamp(values)
{
Var MyArray = 0;
Var NumValues = 0;
Var xBar = 0;
Var SumxBar = 0;
Var i=0;
if (IsArray(values)){
MyArray = values;
}
else {
MyArray = ListToArray(values);
}
NumValues = ArrayLen(MyArray);
xBar = ArrayAvg(MyArray);
for (i=1; i LTE NumValues; i=i+1) {
SumxBar = SumxBar + (MyArray[i] - xBar)*(MyArray[i] - xBar);
}
Return SumxBar/(NumValues-1);
}
``````

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