Let X denote the number of talls in two tosses of a coin. If the mean and the variance of X are $\mu $ and $σ^2$ respectively, than $\mu + σ^2 $ is equal to : |
$\frac{3}{2}$ 1 2 $\frac{5}{2}$ |
$\frac{3}{2}$ |
The correct answer is Option (1) → $\frac{3}{2}$ X → No. of tails (in 2 tosses)
$μ=E(X)=∑P_i(X)X_i=\frac{1}{2}+\frac{1}{2}=1$ $E(X^2)=∑P_i(X){X_i}^2=\frac{1}{2}+1=\frac{3}{2}$ $σ^2+μ=E(X^2)-E^2(X)+E(X)$ $=\frac{3}{2}-1+1$ $=\frac{3}{2}$ |