Chapter 3 - Section 3-4 - Mean and Variance of a Discrete Random Variable - Exercises - Page 77: 3-75

$\mathbb{E}(X)=0.3$ $\operatorname{Var}(X)=0.0576$

$\mathbb{E}(X)=0 \times 0.72+1 \times 0.26+2 \times 0.02=0.3$ $\mathbb{E}\left(X^{2}\right)=0^{2} \times 0.72+1^{2} \times 0.26+2^{2} \times 0.02=0.1476$ $\operatorname{Var}(X)=\mathbb{E}\left(X^{2}\right)-\mathbb{E}(X)^{2}=0.0576$