Often in statistics we’re interested in determining the p-value associated with a certain t-score that results from a hypothesis test. If this p-value is below some significance level, we can reject the null hypothesis of our hypothesis test.

To find the p-value associated with a t-score in R, we can use the pt() function, which uses the following syntax:

**pt(q, df, lower.tail = TRUE)**

where:

**q:**The t-score**df:**The degrees of freedom**lower.tail:**If TRUE, the probability to the left of**q**in the t distribution is returned. If FALSE, the probability to the right is returned. Default is TRUE.

The following examples illustrate how to find the p-value associated with a t-score for a left-tailed test, right-tailed test, and a two-tailed test.

**Left-tailed test**

Suppose we want to find the p-value associated with a t-score of **-0.77** and df = **15 **in a left-tailed hypothesis test.

#find p-value pt(q=-.77, df=15, lower.tail=TRUE) [1] 0.2266283

The p-value is **0.2266**. If we use a significance level of α = 0.05, we would fail to reject the null hypothesis of our hypothesis test because this p-value is not less than 0.05.

**Right-tailed test**

Suppose we want to find the p-value associated with a t-score of **1.87** and df = **24 **in a right-tailed hypothesis test.

#find p-value pt(q=1.87, df=24, lower.tail=FALSE) [1] 0.03686533

The p-value is **0.0368**. If we use a significance level of α = 0.05, we would reject the null hypothesis of our hypothesis test because this p-value is less than 0.05.

**Two-tailed test**

Suppose we want to find the p-value associated with a t-score of **1.24 **and df = **22 **in a two-tailed hypothesis test.

#find two-tailed p-value 2*pt(q=1.24, df=22, lower.tail=FALSE) [1] 0.228039

*To find this two-tailed p-value we simply multiplied the one-tailed p-value by two.*

The p-value is **0.2280**. If we use a significance level of α = 0.05, we would fail to reject the null hypothesis of our hypothesis test because this p-value is not less than 0.05.

**Related: **You can also use this online T Score to P Value Calculator to find p-values.