ThmDex – An index of mathematical definitions, results, and conjectures.
F10505
Formulation 0
Let $X \in \text{Random}(\mathbb{R})$ be a D3161: Random real number such that
(i) \begin{equation} \mathbb{E} |X|^2 < \infty \end{equation}
Then \begin{equation} \text{Var} X = \mathbb{E}(X^2) - (\mathbb{E} X)^2 \end{equation}