Question

For random variable x, it is known that e[x] = 2 and v ar(x) = 3. find e[x2

Answer 1

`\mathbb V(X)=\mathbb E(X^2)-\mathbb E(X)^2`

`\implies3=\mathbb E(X^2)-2^2`

`\implies\mathbb E(X^2)=7`