PdfBinomial Method |
Namespace: Imsl.Stat
Method Pdf.Binomial evaluates the probability that a binomial random variable with parameters n and p with p=pin takes on the value k. It does this by computing probabilities of the random variable taking on the values in its range less than (or the values greater than) k. These probabilities are computed by the recursive relationship
To avoid the possibility of underflow, the probabilities are computed forward from 0, if k is not greater than , and are computed backward from n, otherwise. The smallest positive machine number, , is used as the starting value for computing the probabilities, which are rescaled by if forward computation is performed and by if backward computation is done.
For the special case of p = 0, Pdf.Binomial is set to 0 if k is greater than 0 and to 1 otherwise; and for the case p = 1, Pdf.Binomial is set to 0 if k is less than n and to 1 otherwise.