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Variance
Returns the statistic variance of all instances of a field or array. The variance is defined as
where M is the mean of values in a field and N is the number of values in a field.
Usage:
Variance( fld ) Variance( fld, condFld ) Variance( fld, condFld, cond ) Variance( array )
Parameters:
fld | The name of a field whose values should be used to calculate the variance. |
---|---|
condFld | The name of the field that groups the values of fld (if fld isn't an array). |
cond | A string declaring the type of grouping to be used on condFld. This only makes sense for groups based on Date, DateTime, Time, and Boolean fields. See Summary Field Conditions for a list of strings you can use here. |
array | The name of an array variable whose values should be used to calculate the variance. |
Returns:
A number.
Examples:
//returns the value of variance for a field Temperature grouped by Region variance({data.Temperatur}, {data.Region})
// connection of values, average and variance local numbervar array dataset1 := [3,3,3,3,3]; local numbervar array dataset2 := [1,2,3,4,5];
average(dataset1); // is 3 average(dataset2); // is 3 as well!
variance(dataset1); // is 0 because all values match the average variance(dataset2); // is 2.5 because the values are scattered
Notes:
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If the values in fld should be grouped, a group based on condFld is needed. If the group does not exist in the report, you can add it using i-net Designer or using API method: Engine.addGroup.