Joke: One Friend or Two

A joke to help in recalling the purpose of Correlation and Regression. The joke was written in 2017 by Dennis Pearl from Penn State University based on a joke often told in mathematics (comparing different mathematics topics and ending with the punchline: "Geometry is where I draw the line."). Other options for comparison to regression can be similarly added to the punchline here.  For example “I’ll do prediction, I’ll do forecasting, but regression is where I draw the line,” was suggested by Larry Lesser from The University of Texas at El Paso in 2025.