To compare the means of two populations which cannot be assumed to be normally distributed and only ordinal-level data is available from two independent samples, we should use the t test for independent samples rather than the Mann-Whitney U test.

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Quizplus · Accepted Answer

Since the data is only at the ordinal level, we cannot assume normality of the populations. Therefore, the appropriate test to use is the Mann-Whitney U test, which does not assume normality. The t test assumes normality and should only be used when the data can be assumed to come from normal distributions.

To Compare the Means of Two Populations Which Cannot Be