vault backup: 2023-12-19 14:05:30

education/statistics/Correlation and Regression.md

@@ -29,9 +29,9 @@ If $x$ is above average, we expect the $y$ to be above average if there's a stro
 ## Calculating $r$ by hand
 Put the $x$ values into $L1$, put the $y$ values into $L2$. 
 
-1. Convert the $x$ each x value in the list to standard units($z$). Convert each $y$ value to standard units.
+1. Convert the $x$ each x value in the list to standard units($z$). Convert each $y$ value to standard units. This will create two new tables containing $z_x$ and $z_y$.
 $$ z = \frac{x-\bar{x}}{\sigma_x} $$
-2. Multiply the standard units for each ($x$, $y$) pair in the sets, giving you a third list, named $p$ in this example.
+2. Multiply the standard units for each ($z_x$, $z_y$) pair in the sets, giving you a fifth list, named $p$ in this example.
 $$ x * y = p$$
 3. Find the average of the values from step 3, this is $r$.
 $$ \bar{x}(p) $$