Which non-parametric test is the most appropriate substitute for a one-way ANOVA when the data are ordinal and the normality assumption is violated across three independent groups?

• A Wilcoxon signed-rank test
• B Mann-Whitney U test
• C Friedman test
• D Kruskal-Wallis test ✓

Explanation

The Kruskal-Wallis test is the non-parametric analogue of one-way ANOVA; it compares rank sums across three or more independent groups without assuming normality. The Mann-Whitney U is restricted to two independent groups. The Wilcoxon signed-rank test is for paired/matched data. The Friedman test is for repeated measures across multiple time points in the same subjects.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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