Point biserial correlation

The point biserial correlation gives an estimate of the degree of relationhsip between a dichotomous variable and a continuous variable. One typical use of r pb is correlating a single test item, which is dichotomous (e.g., yes-no), with the overall test score, which is continuous.
For example, a neuropsychologist wanted to determine whether fine motor performance, as measured by speed of finger tapping, was related to gender in an older sample of males and females.

In a research paper, the rpb might be reported as follows:
There was a strong and significant negative correlation found between gender and fine motor movement r(8)=-0.68,p<0.05; in other words, older males are associated with slower fine motor movements, and older females appear to have faster fine motor movements.