[bī¦nō·mē·əl ‚ran·dəm ′ver·ē·ə·bəl] (statistics) A random variable, parametrized by a positive integer n and a number p in the closed interval between 0 and 1, whose range is the set {0, 1, …, n} and whose value is the number of successes in n independent binomial trials when p is the probability of success in a single trial.