Correct Answer - Option 4 : 6
Concept:
Binomial distribution:
If a random variable X has binomial distribution as B (n, p) with n and p as parameters, then the probability of random variable is given as:
P( X = k) = nCk pk q(n - k) where q = p - 1, n is the number of observations, p is the probability of success & q is the probability of failure.
Note: The mean of a binomial distribution is np and variance is npq.
Calculation:
Given: n = 25, p = 2/5, q = 3/5.
As we know that, variance of a binomial distribution = npq
\(\rm ⇒variance = 25 \times \frac{2}{5} \times \frac{3}{5}=6\)
Hence, the correct option is 4.
