What is the Mann-Whitney U test used for?
The Mann-Whitney U test is used to compare whether there is a difference in the dependent variable for two independent groups. It compares whether the distribution of the dependent variable is the same for the two groups and therefore from the same population.
How do you interpret the results of Mann-Whitney U test?
When computing U, the number of comparisons equals the product of the number of values in group A times the number of values in group B. If the null hypothesis is true, then the value of U should be about half that value. If the value of U is much smaller than that, the P value will be small.
Why use Mann-Whitney U test instead of t-test?
Unlike the independent-samples t-test, the Mann-Whitney U test allows you to draw different conclusions about your data depending on the assumptions you make about your data's distribution. … These different conclusions hinge on the shape of the distributions of your data, which we explain more about later.
What is the null hypothesis for Mann-Whitney test?
The null hypothesis for the test is that the probability is 50% that a randomly drawn member of the first population will exceed a member of the second population. Another option for the null hypothesis is that the two samples come from the same population (i.e. that they both have the same median).
What is Mann-Whitney test in statistics?
In statistics, the Mann–Whitney U test (also called the Mann–Whitney–Wilcoxon (MWW/MWU), Wilcoxon rank-sum test, or Wilcoxon–Mann–Whitney test) is a nonparametric test of the null hypothesis that, for randomly selected values X and Y from two populations, the probability of X being greater than Y is equal to the …
Does parametric mean normally distributed?
Parametric tests are suitable for normally distributed data. Nonparametric tests are suitable for any continuous data, based on ranks of the data values. Because of this, nonparametric tests are independent of the scale and the distribution of the data.
What does p-value mean in Mann-Whitney test?
Minitab uses the Mann-Whitney statistic to calculate the p-value, which is a probability that measures the evidence against the null hypothesis.