root.svg Creator: ROOT Version 5.30/01 CreationDate: Thu Sep 6 11:25:25 2012 \larger[2]$x$ 0 0.5 1 1.5 2 2.5 3 3.5 \larger[2]$y$ 0 0.5 1 1.5 2 2.5 3 3.5 0 20 40 60 80 100 120 140 \larger[2]$z(x,y) = \frac{1}{\sigma_x\sigma_y\sqrt{4\pi^2}}\exp\left(- \left(\frac{(x-\mu_x)^2}{2\sigma_x^2} + \frac{(y-\mu_y)^2}{2\sigma_y^2} \right)\right)$