Binomial Distribution

The binomial distribution counts how many successes happen in a fixed number of independent tries, each with the same chance of success: how many of 20 parts pass inspection, how many of 10 calls are answered.

Write Binomial(trials, p), where trials is a whole number and p is the success probability between 0 and 1:

Binomial(10, 0.3)

counts successes in 10 tries at 30 percent each, averaging 3. Use it for a pass-or-fail count out of a known number of attempts.