Understanding the Chi-Square Test Beyond the Formula

The Chi-Square test for independence is explained using an example of book sales versus cover design to determine if two categorical variables are related. It details the process of formulating null and alternative hypotheses and calculating expected counts under the assumption of independence. The Chi-Square statistic is then computed by summing the standardized squared differences between observed and expected values. This calculated statistic is compared to a critical value from the Chi-Square distribution to conclude whether the association is statistically significant.