If the mean and standard deviation of a binomial distribution are 20 and 4 , respectively, then the number of trials is ________

Step-by-step solution

Given, mean of a binomial distribution = 20 ⇒   n p = 20               … i and standard deviation of a binomial distribution = 4 ⇒   n p 1 - p = 4                         … ii Put n p = 20 from equation i to equation ii , we get ⇒   20 1 - p = 4 ⇒   p = 4 5 Put the value of p in the equation i , we get ⇒   n 4 5 = 20 ⇒   n = 25