Let $X \in \text{Random}(\mathbb{R})$ be a D3161: Random real number such that

(i)	\begin{equation} \exists \, a, b \in \mathbb{R} : \mathbb{P}(X \in [a, b]) = 1 \end{equation}

Then \begin{equation} \text{Var} X \leq \frac{(b - a)^2}{4} \end{equation}