Update README.md

Author: r0f1

README.md

@@ -78,6 +78,7 @@ Python debugger (pdb) - [blog post](https://www.blog.pythonlibrary.org/2018/10/1
 [Al-Saleh - Properties of the Standard Deviation that are Rarely Mentioned in Classrooms](http://www.stat.tugraz.at/AJS/ausg093/093Al-Saleh.pdf)   
 [Wainer - The Most Dangerous Equation](http://www-stat.wharton.upenn.edu/~hwainer/Readings/Most%20Dangerous%20eqn.pdf)  
 [Gigerenzer - The Bias Bias in Behavioral Economics](https://www.nowpublishers.com/article/Details/RBE-0092)  
+[Cook - Estimating the chances of something that hasn’t happened yet](https://www.johndcook.com/blog/2010/03/30/statistical-rule-of-three/)  
 
 #### Statistical Tests and Packages
 [researchpy](https://github.com/researchpy/researchpy) - Helpful `summary_cont()` function for summary statistics (Table 1).