| Pré. | Proc. |
bdtr
Binomial distribution.SYNOPSIS:
int k, n;
double p, y, bdtr();
y = bdtr(k, n, p);
DESCRIPTION:
Returns the sum of the terms 0 through k of the Binomial probability density:
k
-- ( n ) j n-j
> ( ) p (1-p)
-- ( j )
j=0
The terms are not summed directly; instead the incomplete beta integral is employed, according to the formula:
y = bdtr(k, n, p) = incbet(n-k, k+1, 1-p).
The arguments must be positive, with p ranging from 0 to 1.
ACCURACY:
Tested at random points (a,b,p), with p between 0 and 1.
a,b Relative error:
arithmetic domain # trials peak rms
For p between 0.001 and 1:
IEEE 0,100 100000 4.3e-15 2.6e-16
ERROR MESSAGES:
message condition value returned
domain k < 0 0.0
n < k
x < 0, x > 1