Description
Covariance is the measure of the linear relation between paired variables (that is, the tendency of two fields to vary together).
Overloads
Covariance (fld, fld, condFld)
Covariance (fld, fld, condFld, cond)
Arguments
fld is any numeric field that can be evaluated by the function.
condFld is a field used to group the values in fld by.
cond is a String indicating the type of grouping for condFld. You only specify this argument when condFld is a Date, Time, DateTime or Boolean field. For more information on the valid strings for this argument, see
Conditions for summary functions.
Action
Covariance is the measure of the linear relation between paired variables (that is, the tendency of two fields to vary together). Fields are covariant when they vary according to a specific mathematical relationship. The circumference of a circle and the radius of a circle are covariant.
Examples
Covariance({table.FIELD1}, {table.FIELD2})
Calculates the covariance of the two fields and returns the covariance as a fractional number.
Using this function in a formula forces the formula to be evaluated at print time.
For more information on evaluation time considerations, see
Evaluation Time.
Comments
Covariance is calculated using the following technique:
It calculates the average (mean) value for the items in each sample.
It subtracts the average value from the value of each item, in both samples.
It multiplies the differences for each pair of items.
It calculates the average (mean) value for all the products of that multiplication. The result is the covariance.