BETAI(3)

SYNOPSIS
REAL FUNCTION BETAI (X, PIN, QIN)

NAME
betai - Calculate the incomplete Beta function.

LIBRARY
SLATEC (FNLIB)

CATEGORY
C7F

TYPE
SINGLE PRECISION (BETAI-S, DBETAI-D)

KEYWORDS
FNLIB, INCOMPLETE BETA FUNCTION, SPECIAL FUNCTIONS

AUTHOR
Fullerton, W., (LANL)

DESCRIPTION
BETAI calculates the REAL incomplete beta function. The incomplete beta function ratio is the probability that a random variable from a beta distribution having parameters PIN and QIN will be less than or equal to X. -- Input Arguments -- All arguments are REAL. X upper limit of integration. X must be in (0,1) inclusive. PIN first beta distribution parameter. PIN must be .GT. 0.0. QIN second beta distribution parameter. QIN must be .GT. 0.0.

REFERENCES
Nancy E. Bosten and E. L. Battiste, Remark on Algorithm 179, Communications of the ACM 17, 3 (March 1974), pp. 156.

ROUTINES CALLED
ALBETA, R1MACH, XERMSG

REVISION HISTORY (YYMMDD)
770401 DATE WRITTEN
890531 Changed all specific intrinsics to generic. (WRB)
890531 REVISION DATE from Version 3.2
891214 Prologue converted to Version 4.0 format. (BAB)
900315 CALLs to XERROR changed to CALLs to XERMSG. (THJ)
900326 Removed duplicate information from DESCRIPTION section. (WRB)
920528 DESCRIPTION and REFERENCES sections revised. (WRB)