The distribution of a count depends on how the data are produced. There are a fixed number n of observations. The n observations are all independent ; that is, knowing the result of one. Each observation falls into one of just two categories, which for convenience we observation does not change the probabilities we assign to other observations call success and failure The probability of a success, call it p , is the same for each observation. The count x of successes in the binomial setting has the binomial distribution with parameters n and p the parameter n is the number of observations, and p is the probability of a success of any one observation. The possible values of x and the whole numbers from 0 to n. Binomial distributions are an important class of discrete probability distributionspay attention to the binomial setting because not all counts have binomial distributions.