BMJ 1996; 312 doi: (Published 02 March 1996) Cite this as: BMJ 1996;312:572

Calculating correlation coefficients with repeated observations: Part 2—correlation between subjects

An authors' error occurred in this Statistics Note (11 March 1995, p 633). The formula for a weighted correlation coefficient had a superior 2 missing in the denominator. The full formula should have read: (Sigma)mixiyi - (Sigma)mixi(Sigma)miyi/(Sigma)mi/(square root) ((Sigma)mix2i - ((Sigma)mixi2/(Sigma)mi ((Sigma)miy2i - ((Sigma)miyi)2/(Sigma)mi


View Abstract