Mathematics
The Chi-Squared Test for Categorical Data and Independence
Quick fact
The chi-squared test was developed by Karl Pearson in 1900 and is one of the most widely used statistical tests in research.
Why this is interesting
Have you ever wondered if your coffee preference is truly linked to your personality type, or if it's just a coincidence? How can we be sure that two categories—like coffee and personality—are actually related in the real world?