bdtrik(y, n, p) = <ufunc 'bdtrik'>¶
Inverse function to
bdtrwith respect to k.
Finds the number of successes k such that the sum of the terms 0 through k of the Binomial probability density for n events with probability p is equal to the given cumulative probability y.
Cumulative probability (probability of k or fewer successes in n events).
Number of events (float).
Success probability (float).
The number of successes k such that bdtr(k, n, p) = y.
Formula 26.5.24 of  is used to reduce the binomial distribution to the cumulative incomplete beta distribution.
Computation of k involves a search for a value that produces the desired value of y. The search relies on the monotonicity of y with k.
Wrapper for the CDFLIB  Fortran routine cdfbin.
Milton Abramowitz and Irene A. Stegun, eds. Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables. New York: Dover, 1972.
Barry Brown, James Lovato, and Kathy Russell, CDFLIB: Library of Fortran Routines for Cumulative Distribution Functions, Inverses, and Other Parameters.