Mann–Whitney U Test

  • Thomas W. MacFarland
  • Jan M. Yates


The Mann–Whitney U test is often viewed as the nonparametric equivalent of Student’s t-Test for Independent Samples, but this comparison may be somewhat too convenient. The two tests (the nonparametric Mann–Whitney U-Test and the parametric Student’s t-Test for Independent Samples) may have similar purposes in that they are both used to determine if there are statistically significant differences between two groups. However, the Mann–Whitney U-Test is used with nonparametric data (typically, ordinal data) whereas the Student’s t-Test for Independent Samples is used with data that meet the assumptions associated with parametric distributions (typically interval data that approximate an acceptable level of normal distribution). Even so, the Mann–Whitney U-Test has many appropriate uses and it should be considered when using ranked data, data that deviate from acceptable distribution patterns, or for when there are noticeable differences in the number of subjects in the two comparative groups.


Anderson-Darling Test Bar plot (stacked, side-by-side) Box plot Code Book Comma-separated values (.csv) Continuous scale Density plot Descriptive statistics Distribution-free Frequency distribution Histogram Interval Mann–Whitney U Test Mean Median Mode Nominal Nonparametric Normal distribution Null hypothesis Ordinal Parametric Probability (p-value) Quantile-Quantile (QQ, Q-Q) Ranking Stacked data Statistical significance Student’s t-Test for Independent Samples Unstacked data 

Supplementary material

385146_1_En_4_MOESM1_ESM.csv (0 kb)
Goats (CSV 1 kb)

Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  • Thomas W. MacFarland
    • 1
  • Jan M. Yates
    • 2
  1. 1.Office of Institutional EffectivenessNova Southeastern UniversityFort LauderdaleUSA
  2. 2.Abraham S. Fischler College of EducationNova Southeastern UniversityFort LauderdaleUSA

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