If the mean and variance of a random variable X having a binomial distribution are 4 and 2 respectively, find P (X = 1).

Given:


Mean=4


Variance=2


P(x=1)=?


P(x=r)= nCr pr qn-r


P(x=1)= nC1 pqn-1


= npqn-1


np(1-p)=2


4(1-p)=2



=q



np=4


n=8


P(x=1)



1