\( \newcommand{\matr}[1] {\mathbf{#1}} \newcommand{\vertbar} {\rule[-1ex]{0.5pt}{2.5ex}} \newcommand{\horzbar} {\rule[.5ex]{2.5ex}{0.5pt}} \newcommand{\E} {\mathrm{E}} \)
deepdream of
          a sidewalk
Show Answer
\( \newcommand{\cat}[1] {\mathrm{#1}} \newcommand{\catobj}[1] {\operatorname{Obj}(\mathrm{#1})} \newcommand{\cathom}[1] {\operatorname{Hom}_{\cat{#1}}} \newcommand{\multiBetaReduction}[0] {\twoheadrightarrow_{\beta}} \newcommand{\betaReduction}[0] {\rightarrow_{\beta}} \newcommand{\betaEq}[0] {=_{\beta}} \newcommand{\string}[1] {\texttt{"}\mathtt{#1}\texttt{"}} \newcommand{\symbolq}[1] {\texttt{`}\mathtt{#1}\texttt{'}} \newcommand{\groupMul}[1] { \cdot_{\small{#1}}} \newcommand{\groupAdd}[1] { +_{\small{#1}}} \newcommand{\inv}[1] {#1^{-1} } \newcommand{\bm}[1] { \boldsymbol{#1} } \require{physics} \require{ams} \require{mathtools} \)
Math and science::INF ML AI

Sum of Gaussian random variables

Sum of Gaussian random variables

Let \( X : \Omega \to \mathbb{R} \) and \( Y : \Omega \to \mathbb{R} \) be two random variables each with a Gaussian distribution:

  • \( X \sim \mathcal{N}(\mu_x, \sigma_x^2) \)
  • \( Y \sim \mathcal{N}(\mu_y, \sigma_y^2) \)

Then the random variable \( Z = X + Y \) has a Gaussian distribution:

\( Z \sim \mathcal{N}(\mu_x + \mu_y, \sigma_x^2 + \sigma_y^2) \)

Follow-up. \( Z = XY \) [does/n't] have a Gaussian distribution?

Can you remember the geometric intuition/proof?