SciPy

scipy.special.ncfdtri

scipy.special.ncfdtri(dfn, dfd, nc, p) = <ufunc 'ncfdtri'>

Inverse with respect to f of the CDF of the non-central F distribution.

See ncfdtr for more details.

Parameters:

dfn : array_like

Degrees of freedom of the numerator sum of squares. Range (0, inf).

dfd : array_like

Degrees of freedom of the denominator sum of squares. Range (0, inf).

nc : array_like

Noncentrality parameter. Should be in range (0, 1e4).

p : array_like

Value of the cumulative distribution function. Must be in the range [0, 1].

Returns:

f : float

Quantiles, i.e. the upper limit of integration.

See also

ncfdtr
CDF of the non-central F distribution.
ncfdtridfd
Inverse of ncfdtr with respect to dfd.
ncfdtridfn
Inverse of ncfdtr with respect to dfn.
ncfdtrinc
Inverse of ncfdtr with respect to nc.

Examples

>>> from scipy.special import ncfdtr, ncfdtri

Compute the CDF for several values of f:

>>> f = [0.5, 1, 1.5]
>>> p = ncfdtr(2, 3, 1.5, f)
>>> p
array([ 0.20782291,  0.36107392,  0.47345752])

Compute the inverse. We recover the values of f, as expected:

>>> ncfdtri(2, 3, 1.5, p)
array([ 0.5,  1. ,  1.5])