Binomial probability distribution represents cases that have multiple but fixed number of trials, like in a coin-toss, with two possible outcomes per trial. Here n denotes the number of trials. In each trial, the probability of success, heads, is denoted by p, whereas the probability of failure, tails, is represented by q. If one is known, the other can be easily calculated. For a binomial distribution, the probability of success or failure should always be the same for all the trials. Also, the outcome of each trial must be independent of other trials. In this example, the number of heads is the random variable, x, whose value can be a whole number between 0 and n. P of x denotes the probability of x heads among n trials, calculated using the Binomial probability formula. Here, the factorial symbol represents the product of decreasing factors. For each value of x, P of x can be obtained, which can be plotted to get the graphical form of the binomial distribution.