
{{alias}}( α, β )
    Returns the standard deviation of a beta prime distribution.

    If `α <= 0` or `β <= 2`, the function returns `NaN`.

    If `α` or `β` is `NaN`, the function returns `NaN`.

    Parameters
    ----------
    α: number
        First shape parameter.

    β: number
        Second shape parameter.

    Returns
    -------
    out: number
        Standard deviation.

    Examples
    --------
    > var v = {{alias}}( 1.0, 2.5 )
    ~1.491
    > v = {{alias}}( 4.0, 12.0 )
    ~0.223
    > v = {{alias}}( 8.0, 2.5 )
    ~8.219

    > v = {{alias}}( 8.0, 1.0 )
    NaN
    > v = {{alias}}( 1.0, -0.1 )
    NaN
    > v = {{alias}}( -0.1, 3.0 )
    NaN

    > v = {{alias}}( 2.0, NaN )
    NaN
    > v = {{alias}}( NaN, 3.0 )
    NaN

    See Also
    --------

