[PS] Start adding more expected values / variance defs

semester4/ps/ps-jh/parts/03_expected-value/01_disc.tex

@@ -10,6 +10,9 @@
 \begin{itemize}
     \item $\cX \sim \text{Ber}(p)$: $\E[\cX] = p$ ($\E[1_A] = \P[A]$)
     \item $\cX \sim \text{Bin}(n, p)$: $\E[\cX] = np$
+    \item $\cX \sim \text{NBin}(r, p)$: $\E[\cX] = \frac{r(1 - p)}{p}$
+    \item $\cX \sim \text{Geom}(p)$: $\E[\cX] = \frac{1}{p}$
+    \item $\cX \sim \text{H}(n, r, m)$: $\E[\cX] = m\frac{n}{r}$
     \item $\cX \sim \text{Poisson}(\lambda)$: $\E[\cX] = \lambda$
 \end{itemize}