The mean and variance of a random variable X having a binomial distribution are `4 and 2` respectively. The `P(X=1)` is

Explanation

Given:

Mean `=4 = np`

Variance `=npq= 2`

`Rightarrow q=1/2 Rightarrow p=1/2`

`n=4/p = 8`

`P(X=1) = 8 *C_1 p^1q^(8-1) = 8*1/2*1/(2)^7 = 1/32`