Cumulative Density Function (CDF) of the noncentral T Distribution

ASA243 is a FORTRAN90 library which computes the cumulative density function (CDF) of the noncentral Student's T probability density function, by Russell Lenth.

ASA243 is Applied Statistics Algorithm 243.


ASA243 is available in a C version and a C++ version and a FORTRAN77 version and a FORTRAN90 version and a MATLAB version

Related Data and Programs:

ASA005, a FORTRAN90 library which evaluates the CDF of the noncentral T distribution.

ASA076, a FORTRAN90 library which evaluates the Owen's T function, needed to compute the CDF of the noncentral T distribution.

OWENS, a FORTRAN90 library which evaluates Owen's T function.


Original FORTRAN77 version by Russell Lenth; FORTRAN90 version by John Burkardt.


  1. William Guenther,
    Evaluation of probabilities for the noncentral distributions and difference of two T-variables with a desk calculator,
    Journal of Statistical Computation and Simulation,
    Volume 6, Number 3-4, 1978, pages 199-206.
  2. Russell Lenth,
    Algorithm AS 243: Cumulative Distribution Function of the Non-Central T Distribution,
    Applied Statistics,
    Volume 38, Number 1, 1989, pages 185-189.

Source Code:

Examples and Tests:

List of Routines:

You can go up one level to the FORTRAN90 source codes.

Last revised on 25 January 2008.