What is mann whitney u test spss?

The Mann-Whitney U test (also known as the Mann-Whitney-Wilcoxon test) in SPSS is a nonparametric test used to compare two independent groups on a continuous or ordinal dependent variable. This test is used when the assumption of normality is violated or cannot be tested due to small sample sizes.

The test measures the difference between the two groups in terms of their median ranks. It is based on the ranks of the observations in the combined sample and calculates the sum of the ranks for each group. The U statistic represents the smaller sum of the two ranked sums and is used to determine the significance of the difference between the two groups.

SPSS provides output for the Mann-Whitney U test that includes the U statistic, the exact p-value, and a confidence interval for the median difference between the two groups. Additionally, graphical representations of the data distribution and box plots are also displayed in the output.

The Mann-Whitney U test is commonly used in research studies to compare two groups, such as experimental and control groups, or two different treatment options. It is also used in healthcare research to compare the effectiveness of different treatment options on patient outcomes, or in educational research to compare the performance of students in different groups.