Understanding Correlation in PHP: Pearson vs Spearman vs Kendall Tau

A PHP article explains the basics of correlation and compares Pearson, Spearman, and Kendall tau.

It shows when to use each method for linear, ranked, or monotonic data, and how outliers can affect results.

The article includes practical examples using the hi-folks/statistics package and its Stat class.

It also reminds developers not to confuse correlation with causation.