0 0 m -1 0.333 l -1 -0.333 l h 0 0 m -1 0.333 l -1 -0.333 l h 0.6 0 0 0.6 0 0 e 0.4 0 0 0.4 0 0 e 0.6 0 0 0.6 0 0 e 0.5 0 0 0.5 0 0 e 0.6 0 0 0.6 0 0 e 0.4 0 0 0.4 0 0 e -0.6 -0.6 m 0.6 -0.6 l 0.6 0.6 l -0.6 0.6 l h -0.4 -0.4 m 0.4 -0.4 l 0.4 0.4 l -0.4 0.4 l h -0.6 -0.6 m 0.6 -0.6 l 0.6 0.6 l -0.6 0.6 l h -0.5 -0.5 m 0.5 -0.5 l 0.5 0.5 l -0.5 0.5 l h -0.6 -0.6 m 0.6 -0.6 l 0.6 0.6 l -0.6 0.6 l h -0.4 -0.4 m 0.4 -0.4 l 0.4 0.4 l -0.4 0.4 l h -0.43 -0.57 m 0.57 0.43 l 0.43 0.57 l -0.57 -0.43 l h -0.43 0.57 m 0.57 -0.43 l 0.43 -0.57 l -0.57 0.43 l h 0 0 m -1 0.333 l -1 -0.333 l h 0 0 m -1 0.333 l -0.8 0 l -1 -0.333 l h 0 0 m -1 0.333 l -0.8 0 l -1 -0.333 l h -1 0.333 m 0 0 l -1 -0.333 l 0 0 m -1 0.333 l -1 -0.333 l h -1 0 m -2 0.333 l -2 -0.333 l h 0 0 m -1 0.333 l -1 -0.333 l h -1 0 m -2 0.333 l -2 -0.333 l h 128 704 m 256 704 l 160 672 m 160 800 l $\mu_Y$ $\mu_X$ 144 752 m 256 752 l 208 688 m 208 800 l $+ * + = +$ $- * - = +$ $- * + = -$ $+ * - = -$ $(X-\mu_X) * (Y-\mu_Y)$