Introduction to Chi-squared
Chi-squared Bead Activity
Introduction to Homogeneity Test
Chi-squared practice problem: Rubric
Practice problem assignment
Test for Independence Assignment

Karl Pearson, a professor at University College in London, was the first person to develop a family of curves directly related to biological data he was describing. The data he was studying could not be placed into normal distributions. In 1900 he developed the first chi-squared test. It is considered to be the oldest inference procedure still in use.

The chi-square procedure helps to investigate not only individual proportions, but entire proportion distributions.