Point-biserial correlation coefficient
（重定向自Point biserial correlation）
The point biserial correlation coefficient (rpb) is a correlation coefficient used when one variable (e.g. Y) is dichotomous; Y can either be "naturally" dichotomous, like gender, or an artificially dichotomized variable. In most situations it is not advisable to dichotomize variables artificially. When you artificially dichotomize a variable the new dichotomous variable may be conceptualized as having an underlying continuity. If this is the case, a biserial correlation would be the more appropriate calculation.