In the theory of probability and statistics, a Bernoulli trial (or binomial trial) is a random experiment with exactly two possible outcomes, "success" and "failure", in which the probability of success is the same every time the experiment is conducted. It is named after Jacob Bernoulli, a 17th-century Swiss mathematician, who analyzed them in his Ars Conjectandi (1713). Since a Bernoulli trial has only two possible outcomes, it can be framed as some "yes or no" question. For example: * Is the top card of a shuffled deck an ace? * Was the newborn child a girl? (See human sex ratio.)