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Mathematics

The Chi-Square Test for Independence in Contingency Tables

Quick fact

The chi-square test for independence can detect whether two categorical variables, like 'pizza preference' and 'movie taste,' are related, and it was developed by Karl Pearson in 1900, who also invented the correlation coefficient.

Why this is interesting

You're at a party and notice that people who like pineapple pizza also seem to love terrible movies. Is that a real pattern or just coincidence? How can we tell with numbers?