The T_PDF function computes the probability P that, in a Student's t distribution with Df degrees of freedom, a random variable X is less than or equal to a user-specified cutoff value V .
This routine is written in the IDL language. Its source code can be found in the file
subdirectory of the IDL distribution.
Use the following command to compute the probability that a random variable X, from the Student's t distribution with 15 degrees of freedom, is less than or equal to 0.691. The result should be 0.749940.