MannWhitney test (independent samples)
DescriptionThe MannWhitney test is the nonparametric equivalent of the independent samples ttest. It should be used when the sample data are not Normally distributed, and they cannot be transformed to a Normal distribution by means of a logarithmic transformation. Required inputSelect the variables for sample 1 and sample 2. You can use the button to select variables and filters in the variables list. ResultsThe MannWhitney test (independent samples) combines and ranks the data from sample 1 and sample 2 and calculates a statistic on the difference between the sum of the ranks of sample 1 and sample 2. When either or both sample sizes are large (>20) then MedCalc uses the Normal approximation (Lentner, 1982) to calculate the Pvalue. For small sample sizes, in the absence of ties, MedCalc calculates the exact probability (Conover, 1999). If the resulting Pvalue is small (P<0.05) then a statistically significant difference between the two samples can be accepted. Literature
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