diff --git a/education/statistics/Correlation and Regression.md b/education/statistics/Correlation and Regression.md
index a0a493f..f5aef14 100644
--- a/education/statistics/Correlation and Regression.md	
+++ b/education/statistics/Correlation and Regression.md	
@@ -106,6 +106,10 @@ $$ y = mx + b $$
 Where $y$ is the predicted value, $m$ is the slope, $x$ is the given value and the $b$ is the intercept. 
 $$ slope = \frac{r * \sigma_y}{\sigma_x} $$
 
+#### Residual plots
+A plot of the differences from the line. Makes it easier to see if the data is football shaped.
+If a residual plot has a strong pattern, it may not be suitable for making predictions. 
+
 ### The Regression Effect
 - In a test-retest situation, people with low scores tend to improve, and people with high scores tend to do worse. This means that individuals score closer to the average as they retest. 
 - The regression *fallacy* is contributing this to something other than chance error.