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Correlationbeforereadingbasicsyntaxcrystalsyntax

Returns the correlation value of two fields or arrays. A correlation is a number that describes the degree of relationship between two fields. The correlation coefficient may take on any value between plus and minus one.

Usage:

Correlation( fld, fld )
Correlation( fld, fld, condFld )
Correlation( fld, fld, condFld, cond )

Parameters:

fld	The name of a field or array variable whose values should be used to calculate the correlation value.
condFld	The name of the field that groups the values of both fields (if both fields are not arrays).
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.

Returns:

A fractional number.

Examples:

//computes the correlation between the values of a field "production" of table "factory"
//and the values of a field "faults" of a table "material".
correlation({factory.production},{material.faults})

//computes the correlation of two arrays
correlation([1,2,3,4,5,6],[1,2,1,2,3,1])	//returns 0.26

//computes the correlation of the return value (has to be an array)
//of the formula fields "makeArrayFemales" ans "makeArrayMales"
correlation({@makeArrayFemales}, {@makeArrayMales})

//computes the correlation between factory production and material faults grouped by vendor
correlation({factory.production},{material.faults},{Vendors.VendorID})

Notes:

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.
An undefined correlation due to a variance of zero will result in a value of 1.