Update positive_continuous_distributions.qmd

Author: bob-carpenter

src/functions-reference/positive_continuous_distributions.qmd

@@ -365,7 +365,7 @@ If the shape parameter $\alpha \in \mathbb{R}^+$ and the rate (or inverse scale)
 \frac{\beta^{\alpha}}      {\Gamma(\alpha)} \, y^{\alpha - 1}
 \exp(-\beta \, y) . \end{equation*}
 
-Under the shape and rate formulation of the Gamma distribution, $E(y) = \alpha/\beta$ and $\text{Var}(y) = \alpha/\beta^2$.
+Under the shape and rate formulation of the Gamma distribution, $\mathbb{E}[y] = \alpha / \beta$ and $\textrm{var}[y] = \alpha / \beta^2$.
 
 ### Distribution statement