In which situation is a point-biserial correlation used?

In which situation is a point-biserial correlation used?

• A. When both variables are continuous.
• B. When one variable is dichotomous and the other is continuous.
• C. When both variables are dichotomous.
• D. When data are ordinal.

Answer: (B)

Point-biserial correlation measures the association between a binary (dichotomous) variable and a continuous variable. It’s a form of Pearson correlation applied when one variable is coded as 0/1, capturing how the continuous scores differ on average between the two groups. This makes it the right tool when you have a yes/no type variable (for example, treatment vs. no treatment) and a continuous outcome (like test scores). If both variables were continuous, you’d use Pearson correlation; if both were dichotomous, you’d use the phi coefficient; and if the data are ordinal, Spearman correlation is more appropriate.

Point-biserial correlation measures the association between a binary (dichotomous) variable and a continuous variable. It’s a form of Pearson correlation applied when one variable is coded as 0/1, capturing how the continuous scores differ on average between the two groups. This makes it the right tool when you have a yes/no type variable (for example, treatment vs. no treatment) and a continuous outcome (like test scores). If both variables were continuous, you’d use Pearson correlation; if both were dichotomous, you’d use the phi coefficient; and if the data are ordinal, Spearman correlation is more appropriate.