R (symmetric beta) distribution

The probability density function for R-distributed distribution is:

.. math::

f(x, k) = \frac{(1-x^2)^{k/2-1}}{B(1/2, k/2)}

where :math:-1 \le x \le 1, k > 0, and :math:B is the Beta function.

The following plots show the pdf and cdf:

.. image:: ../../../../tests/imgs/stats/continuous/rdist/rdistpdf.png :align: center :width: 480

.. image:: ../../../../tests/imgs/stats/continuous/rdist/rdistcdf.png :align: center :width: 480