Answer:
Mean = 20
Standard deviation ≈ 4.38
Explanation:
X is a random variable with a binomial distribution with p = 4% = 0.04 and n = 500, where p stands for probability of success and n stands for number of trials.
1. The mean of binomial distribution is given as np, therefore the mean would be
500 x 0.04 = 20
2. The standard deviation of a binomial distribution is given as √[np(1 – p)], therefore we have:
√[500 x 0.04(1 – 0.04)] = √[20(0.96)] = √(19.2) ≈ 4.38