Purpose of use BinomialDist lower P(1, 30, 0.95) lower P = 5.3178519010543823242E-37 (inverse function): parameters above number of successes x = 6. The Bernoulli distribution is a special case of the Binomial distribution when the number of trails is 1. This expected value calculator helps you to quickly and easily calculate the expected value (or mean) of a discrete random variable X. A binomial probability is the chance of an event occurring given a number of trials and number of successes. The calculator will find the binomial and cumulative probabilities, as well as the mean, variance and standard deviation of the binomial distribution. Enter all known values of X and P(X) into the form below and click the "Calculate" button to calculate the expected value of X. Click on … The Binomial Distribution Calculator will construct a complete binomial distribution and find the mean and standard deviation. Please enter the necessary parameter values, and then click 'Calculate'. Show Instructions In general, you can skip the multiplication sign, so `5x` is equivalent to `5*x`. This calculator will tell you the variance for a binomial random variable, given the number of trials and the probability of success. CALCULATOR. Calculate nq to see if we can use the Normal Approximation: Since q = 1 - p, we have n(1 - p) = 10(1 - 0.4) nq = 10(0.6) nq = 6 Since np and nq are both not greater than 5, we cannot use the Normal Approximation to the Binomial Distribution.cannot use the Normal Approximation to the Binomial Distribution. Variance Calculator for a Binomial Random Variable.