This modular approach avoids having to create new references when adding / changing only one or two fields in a reference, while utilizing all of the already populated reference fields such as ISBN, author, coauthor . ?! 16 : 13, 18 December 2008 ( UTC)
22.
Where " ? " is the correlation coefficient between the test and reference fields, " E " 2 is the centered RMS difference between the fields ( with any difference in the means first removed ), and \ sigma _ r and \ sigma _ t are the variances of the reference and test fields, respectively.
