scipy.special.chdtrc¶
- scipy.special.chdtrc(v, x, out=None) = <ufunc 'chdtrc'>¶
Chi square survival function.
Returns the area under the right hand tail (from x to infinity) of the Chi square probability density function with v degrees of freedom:
\[\frac{1}{2^{v/2} \Gamma(v/2)} \int_x^\infty t^{v/2 - 1} e^{-t/2} dt\]Here \(\Gamma\) is the Gamma function; see
gamma. This integral can be expressed in terms of the regularized upper incomplete gamma functiongammainccasgammaincc(v / 2, x / 2). [1]- Parameters
- varray_like
Degrees of freedom.
- xarray_like
Lower bound of the integral.
- outndarray, optional
Optional output array for the function results.
- Returns
- scalar or ndarray
Values of the survival function.
References
- 1
Chi-Square distribution, https://www.itl.nist.gov/div898/handbook/eda/section3/eda3666.htm
Examples
>>> import scipy.special as sc
It can be expressed in terms of the regularized upper incomplete gamma function.
>>> v = 1 >>> x = np.arange(4) >>> sc.chdtrc(v, x) array([1. , 0.31731051, 0.15729921, 0.08326452]) >>> sc.gammaincc(v / 2, x / 2) array([1. , 0.31731051, 0.15729921, 0.08326452])