FNP_betareturns the value of the probability integral of the univariate beta probability density function with parametersaandbatx,P(x;a,b).P(x;a,b) is defined only fora0 andb0.
P(x;a,b) is defined by the expression
When 0x1,P(x;a,b) is related to the incomplete beta function returned byFNIbeta,Bx(a,b), by the expression
P(x;a,b)
The functionP(x;a,b) is sometimes writtenIx(a,b).
Errors
FNP_betacauses an HTBasic error if its arguments are not all of type REAL or ifaorbis negative.