The nonparametric test for hypothesis testing: the Kruskal-Wallis test and beyond

In their article “Minimal Current Intensity to Elicit an Evoked Motor Response Cannot Discern Between Needle-Nerve Contact and Intraneural Needle Insertion” published in this month’s issue of Anesthesia & Analgesia, Dr. Thomas Weismann, Department of Anesthesiology and Intensive Care Therapy, Philipps University Marburg, University Hospital Giessen-Marburg, Marburg, Germany, and colleagues examined the minimal stimulation current (MSC)(…)

A lesson in statistics: the Wilcoxon-Mann-Whitney odds test for hypothesis testing

In published literature on analgesic-related studies, the Wilcoxon-Mann-Whitney (WMW) rank sum (or signed rank) test is frequently used to analyze outcomes such as morphine consumption in the PACU, antiemetic dose, or some Likert scored outcome such as pain or nausea. These outcomes share the common characteristic of being non-normally distributed. As we all learned in(…)