Question

the random variable X is B(n,0.3) and E(X) =2.4. find n and the standard deviation

Answer 1

Step-by-step explanation:

The standard deviation of X is represented by

image3.jpg

and represents the square root of the variance. If X has a binomial distribution, the formula for the standard deviation is

image4.jpg

where n is the number of trials and p is the probability of success on each trial. For this situation, n = 18 and p = 0.4, so