statsmodels.distributions.discrete.DiscretizedCount.isf

DiscretizedCount.isf(q, *args, **kwds)

Inverse survival function (inverse of sf) at q of the given RV.

Parameters:

  • q (array_like) – Upper tail probability.

  • arg1 (array_like) – The shape parameter(s) for the distribution (see docstring of the instance object for more information).

  • arg2 (array_like) – The shape parameter(s) for the distribution (see docstring of the instance object for more information).

  • arg3 (array_like) – The shape parameter(s) for the distribution (see docstring of the instance object for more information).

  • ... (array_like) – The shape parameter(s) for the distribution (see docstring of the instance object for more information).

  • loc (array_like, optional) – Location parameter (default=0).

Returns:

k – Quantile corresponding to the upper tail probability, q.

Return type:

ndarray or scalar

Notes

For discrete distributions, the sf is not strictly invertible. By convention, this method returns the minimum value k for which the sf at k is no greater than q. There is one exception: the isf of 1 is a-1, where a is the left endpoint of the support.