Measure color according to the numeric area of the normalizing parameter from three eigenvectors in HSV color space for the differencecorrelation among three eigenvectors.
Since there is a strong correlation between these variables and a country's wealth, they controlled for GNP per head by measuring whether it alone accounted for the difference in mating strategy.
Ecker found there was a correlation between the severity of a person's autism and the amount of structural difference observed in their brain scans, compared with the control group.