has_specified_output achieves_planned_objective data transformation between group comparison objective between group comparison statistical test Friedman test Philippe Rocca-Serra The Friedman test is a non-parametric statistical test used to determine whether there are statistically significant differences among multiple related groups. It is an extension of the Wilcoxon signed-rank test for more than two related samples. adapted from wikipedia https://en.wikipedia.org/wiki/Friedman_test and adapted from ChatGPT3.5 with the following prompt: "Please define 'Friedman Test' in statistics" p-value requires discussion