How to Calculate Point-Biserial Correlation in R?

In this article, we will discuss how to calculate Point Biserial correlation in R Programming Language.

Correlation measures the relationship between two variables. we can say the correlation is positive if the value is 1, the correlation is negative if the value is -1, else 0. Point biserial correlation returns the correlated value that exists between a binary variable and a continuous variable. we can calculate the point biserial correlation using the cor.test() function.

Syntax:

cor.test(data1,data2)

Parameters:

• data: Vectors of points

Example 1:

In this example, we will be using the cor.test() function with two vectors containing different data points to get the correlation between them in the R language.

R

# create two vectors
data1=c(1:20)

data2=c(23:42)

# get correlation
print(cor.test(data1,data2))

Output:

    Pearson's product-moment correlation

data:  data1 and data2
t = Inf, df = 18, p-value < 2.2e-16
alternative hypothesis: true correlation is not equal to 0
95 percent confidence interval:
 1 1
sample estimates:
cor 
  1 

Example 2: 

In this example, we will be using the cor.test() function with the different columns of the given data frame get the correlation between them in the R language.

R

# create  dataframe with two columns
data=data.frame(col1=c(1,34,56,32,23),
                col2=c(21,34,56,32,34))

# get correlation
print(cor.test(data$col1,data$col2))

Output:

    Pearson's product-moment correlation

data:  data$col1 and data$col2
t = 4.7383, df = 3, p-value = 0.01782
alternative hypothesis: true correlation is not equal to 0
95 percent confidence interval:
 0.3323372 0.9960865
sample estimates:
      cor 
0.9392161