Module « scipy.special »

Fonction nctdtr - module scipy.special

Signature de la fonction nctdtr

Description

nctdtr.__doc__

nctdtr(x1, x2, x3, /, out=None, *, where=True, casting='same_kind', order='K', dtype=None, subok=True[, signature, extobj])

nctdtr(df, nc, t)

Cumulative distribution function of the non-central `t` distribution.

Parameters
----------
df : array_like
    Degrees of freedom of the distribution. Should be in range (0, inf).
nc : array_like
    Noncentrality parameter. Should be in range (-1e6, 1e6).
t : array_like
    Quantiles, i.e., the upper limit of integration.

Returns
-------
cdf : float or ndarray
    The calculated CDF. If all inputs are scalar, the return will be a
    float. Otherwise, it will be an array.

See Also
--------
nctdtrit : Inverse CDF (iCDF) of the non-central t distribution.
nctdtridf : Calculate degrees of freedom, given CDF and iCDF values.
nctdtrinc : Calculate non-centrality parameter, given CDF iCDF values.

Examples
--------
>>> from scipy import special
>>> from scipy import stats
>>> import matplotlib.pyplot as plt

Plot the CDF of the non-central t distribution, for nc=0. Compare with the
t-distribution from scipy.stats:

>>> x = np.linspace(-5, 5, num=500)
>>> df = 3
>>> nct_stats = stats.t.cdf(x, df)
>>> nct_special = special.nctdtr(df, 0, x)

>>> fig = plt.figure()
>>> ax = fig.add_subplot(111)
>>> ax.plot(x, nct_stats, 'b-', lw=3)
>>> ax.plot(x, nct_special, 'r-')
>>> plt.show()