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Please note that the recommended version of Scilab is 6.1.1. This page might be outdated.
See the recommended documentation of this function

Scilab manual >> Statistics > cdfbet


cumulative distribution function Beta distribution

Calling Sequence




five real vectors of the same size.

P,Q (Q=1-P)

The integral from 0 to X of the beta distribution (Input range: [0, 1].)



X,Y (Y=1-X)

Upper limit of integration of beta density (Input range: [0,1], Search range: [0,1]) A,B : The two parameters of the beta density (input range: (0, +infinity), Search range: [1D-300,1D300] )


Calculates any one parameter of the beta distribution given values for the others (The beta density is proportional to t^(A-1) * (1-t)^(B-1).

Cumulative distribution function (P) is calculated directly by code associated with the following reference.

DiDinato, A. R. and Morris, A. H. Algorithm 708: Significant Digit Computation of the Incomplete Beta Function Ratios. ACM Trans. Math. Softw. 18 (1993), 360-373.

Computation of other parameters involve a seach for a value that produces the desired value of P. The search relies on the monotinicity of P with the other parameter.

From DCDFLIB: Library of Fortran Routines for Cumulative Distribution Functions, Inverses, and Other Parameters (February, 1994) Barry W. Brown, James Lovato and Kathy Russell. The University of Texas.

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Last updated:
Wed Jan 26 16:23:42 CET 2011