Point-biserial correlation with unequal groups in dichotomous variable

The dichotomous variable I want to use for a point-biserial correlation has very unequal n's ($n_1=140$, $n_2=6$). Would this be breaking any rules? What would this mean for my results? Would it just limit the statistical power?

• 1) No, it doesn't break formal assumptions for point-biserial r. 2) Yes it does limit statistical power. – ttnphns Mar 20 '13 at 21:21