The power and type I error of Wilcoxon-Mann-Whitney, Welch's t, and Student's t tests for Likert-type data

Likert-type item is the most popular response format for collecting data in social, educational, and psychological studies through scales or questionnaires. However, there no consensus on whether parametric non-parametric tests should be preferred when analyzing data. This study examined statistical power of each was analyzed independently survey studies. The main purpose to examine Wilcoxon-Mann-Whitney, Welch's t, Student's t data, which are pairwise comparison tests. For this purpose, a Monte Carlo simulation conducted. significance selected under conditions sample size, group size ratio, effect size. results showed that Wilcoxon-Mann-Whitney test superior its counterparts, especially small samples unequal sizes. t-test had similar equal sizes 200 more. Consistent with empirical results, practical recommendations were provided researchers what consider