We know that the mean and variance of a binomial distribution with number of trials as ānā and the probability of success as āpā are Mean = np Variance = np(1-p) Therefore applying the given conditions yields us np=2 np(1āp)=1 2(1āp)=1 1āp=
1
2
p=
1
2
Therefore the number of trials will be 4 P(X=0) =4C0(1āP)4 =
