I Google-searched "pandas corr" and the third result was this question, which solicits (and receives) the exact answer to an assignment (Question #9) I'm working on. Kind of ruins the fun.
This is the question:
Question 9 (6.6%) Create a column that estimates the number of citable documents per person. What is the correlation between the number of citable documents per capita and the energy supply per capita? Use the .corr() method, (Pearson's correlation).
I can see how it's a relatively straightforward question with a broadly applicable answer, and it's efficient to waste energy obscuring the context, and the question received numerous upvotes; so maybe this is how SO is supposed to work. I'm just curious so I know for the future in my own asking/answering.