Mann Whitney test
This test is known as Wilcoxon rank-sum test.
It is a non-parametric statistical test which is generally used to review the distributions between two independent groups.
This is also an alternative to T-test, but we should use this test when our assumptions of normality and equal variances generally not met. This test is also applied to check that medians of two groups are statistically different from each other or not?
This test works on below parameters:
· Ranking
· Calculating U
· Comparison
· Hypothesis testing
· Interpretations
Mann Whitney
T test
Assumptions
No specific distribution assumptions
Applied when data is non-normal and skewed.
Comparing Rank between 2 groups
Assumes data follows a normal distribution.
Comparing with 2 groups with equal variances
Real scenario where Mann-Whitney U test accepts more than T-test.
ü When data is ordinal
ü When we have small samples
ü When we have outliers
ü When our data is skewed
ü When variances are not equal
ü When we have categorical data to compare