/Refresher: A random variable that is Binary can have one of two outcomes. Examples are: a. flip a coin and record the result, b. accept or decline a credit card offer, c. vote yes or no in a referendum, d. pass or fail a quiz. The main outcome of interest is labeled a success. For example, suppose heads, accepting the credit card offer, a yes vote, and failing a quiz were the outcomes of interest in the above examples. These would be the successes. The other outcome is typically called the failure. When a random variable gives the count of the total number of successes, then this random variable has a binomial distribution. The sample size is called the number of trials and each trial is binary and Bernoulli. The sequence of trials is a binomial random variable with probability of success on one trial equal to p. This is frequently denoted Bin(n,p) to mean a binomial distribution with n trials and probability of success p for