Simpson's paradox
Q: If drug B has a higher success rate (%age of cures) than drug A
when given to women, and also when given to men, does it have a higher
success rate when given to people in general?
2 Apr 1997
Q: What's the smallest possible "paradoxical" situation (i.e.
smallest total number of people)? There are two versions of the problem
depending on whether we allow entries to be 0.
2 Apr 1997
Q: Here's another striking version. A greengrocer sells apples at
a fixed price per fruit, and oranges similarly. Each day an apple costs
more than an orange. I buy fruit on several days. On average, did my
apples cost me more per fruit than my oranges?
20 Mar 2011
Q:
Call the above situation a 2-level paradox, because we're
measuring the drugs' effectiveness at two levels: the gender level and
the overall population level. Is it possible to have a 3-level
paradox? For example, is it possible that drug A has a higher success
rate on people, but drug B has a higher success rate on women and on
men, but drug A has a higher success rate on each of young women, old
women, young men and old men?
Haidar Al-Dhalimy, 2 Apr 2021