The Mann-Whitney U test, also known as the Wilcoxon rank-sum test, is a nonparametric method for comparing two independent samples. Ideal for ordinal or continuous data that isn't normally distributed, it assesses differences in central tendencies without the need for normal distribution assumptions. This test is crucial in psychology, education, and medical research, providing a robust alternative to the t-test for non-normal data.
Show More
The Mann-Whitney U test is a nonparametric statistical test used to compare two independent samples
Introduction of the Test
The Mann-Whitney U test was first introduced by Wilcoxon in 1945 and later extended by Mann and Whitney in 1947
Applications of the Test
The Mann-Whitney U test is widely used in various scientific disciplines, including psychology, education, and medical research
The Mann-Whitney U test is used to determine if there are significant differences in the central tendencies of two groups when data do not follow a normal distribution
The samples being compared must be independent, with the selection of one observation not affecting another
The Mann-Whitney U test is appropriate for ordinal or continuous data
The distribution shapes of the two groups should be similar, though their central tendencies may differ
The Mann-Whitney U test involves ranking the combined data from both groups, calculating the U statistic for each group, and determining significance through comparison to a critical value or p-value
The U statistic reflects a significant difference between the groups, but further analysis is needed to determine the direction and magnitude of the difference
The Mann-Whitney U test is widely used in fields such as medical research, psychology, education, and environmental studies
Researchers must ensure sample independence and similar distribution shapes to use the Mann-Whitney U test
Researchers can use random sampling, graphical analysis, larger sample sizes, or alternative methods to address violations of the test's assumptions
00
Initially introduced by ______ in 1945, the test was later expanded by ______ and ______ in 1947.
Wilcoxon
Mann
Whitney
01
Independence of samples for Mann-Whitney U test
Samples must be independent; selection of one observation doesn't affect another.
02
Data types suitable for Mann-Whitney U test
Appropriate for ordinal data (ranked) or continuous data, not for nominal data.
