The sum of all the probabilities is one
BUT the cdf measures probabilties as you move along the x-axis.
The entire sum of probabilities would be the COMPLETE beta function
Now this
http://mathworld.wolfram.com/Incompl...aFunction.html
is incomplete since the upper bound is not 1.
Your integral may be fine, but that sum is complete
I would need to know what the incomplete binomial sum is.
Now this
http://en.wikipedia.org/wiki/Beta_function
has the incomplete beta function and there is a different factorial in the binomial