# How to Calculate Point-Biserial Correlation in Excel

Point-biserial correlation is used to measure the relationship between a binary variable, x, and a continuous variable, y.

Similar to the Pearson correlation coefficient, the point-biserial correlation coefficient takes on a value between -1 and 1 where:

• -1 indicates a perfectly negative correlation between two variables
• 0 indicates no correlation between two variables
• 1 indicates a perfectly positive correlation between two variables

This tutorial explains how to calculate the point-biserial correlation between two variables in Excel.

### Example: Point-Biserial Correlation in Excel

Suppose we have the following binary variable, x, and a continuous variable, y:

To calculate the point-biserial correlation between x and y, we can simply use the =CORREL() function as follows:

The point-biserial correlation between x and y is 0.218163.

Since this number is positive, this indicates that when the variable x takes on the value “1” that the variable y tends to take on higher values compared to when the variable x takes on the value “0.”

We can easily verify this by calculating the average value of y when x is 0 and when x is 1:

When x = 0, the average value of y is 14.2. When x = 1, the average value of y is 16.2. This confirms the fact that the point-biserial correlation between the two variables should be positive.

We can also use the following formulas to calculate the p-value for this correlation coefficient:

The p-value turns out to be 0.5193. Thus, although the correlation coefficient between the two variables is slightly positive it turns out to not be a statistically significant correlation.