The function BinomDistriIntegral returns the integral of the binomial distribution between 0 and k. The parameter SampleSize specifies the size of the drawn sample, the parameter FractionA controls the fraction of items marked "A" (see below). The parameter k may take any value between zero and SampleSize, the parameter FractionA is limited to the interval [0,1]. Both parameters are automatically corrected to the closest limit if an out-of-range value is specified.
Background of the binomial distribution: Let's assume to have a container of a huge (infinite) amount of balls with a certain fraction (parameter FractionA) of them being marked by "A", the others being marked by "B". The binomial distribution provides an answer to the question "what is the probability of getting k "A" balls when drawing SampleSize balls from the container?". The function BinomDistriIntegral calculates the probability of getting any number of "A" balls between zero and k.