A t value is the result of a statistical test. The value is located on the Student’s t distribution that is appropriate for the degrees of freedom. The location specifies the probability of obtaining the t value from chance. If the probability is less than the significance level, the result is judged to be statistically significant
The Student’s t distribution is a theoretical distribution. There are many of these distributions, and each of them differs based on the degrees of freedom.
The t value is typically calculated by taking the difference of observed and expected means and dividing the difference by the standard error.