The Mann Whitney U Test is a nonparametric statistical test used to determine whether there are differences between two independent groups. It's particularly useful when the data does not meet the assumptions necessary for a ttest. This guide will walk you through how to perform the Mann Whitney U Test in Excel, complete with stepbystep instructions, tips, and useful insights. π
Understanding the Mann Whitney U Test
Before diving into the Excel process, it's crucial to understand what the Mann Whitney U Test is and when to use it.
What is the Mann Whitney U Test? π€
The Mann Whitney U Test assesses whether there is a statistically significant difference between the distributions of two independent groups. This test is ideal for:
 Ordinal data: Data that can be ranked but not measured accurately.
 Nonnormal distributions: When your data does not follow a normal distribution.
When to Use the Mann Whitney U Test?
Use the Mann Whitney U Test in the following scenarios:
 You have two independent samples.
 Your data is ordinal or continuous but not normally distributed.
 You want to compare medians between groups.
Preparing Your Data in Excel
To perform the Mann Whitney U Test in Excel, you first need to ensure your data is organized correctly.
Step 1: Organize Your Data π
Arrange your data in two separate columns for the two groups you want to compare. For instance:
Group A  Group B 

5  7 
6  8 
7  9 
8  10 
9  12 
Important Note:
Ensure there are no missing values in your dataset, as this can affect the results of the Mann Whitney U Test.
Steps to Perform Mann Whitney U Test in Excel
Step 2: Rank the Data π
 Combine the Data: Copy all data points from both groups into one column.
 Sort the Combined Data: Select the combined data and sort it from smallest to largest.
 Rank the Data: In the next column, use the
RANK.EQ()
function to assign ranks to each value.
Example Formula
=RANK.EQ(A1, $A$1:$B$10)
Step 3: Calculate the Ranks for Each Group
After ranking the combined data, separate the ranks back into two columns corresponding to each group.
Group A  Group B  Ranks A  Ranks B 

5  7  1  4 
6  8  2  5 
7  9  3  6 
8  10  4  7 
9  12  5  8 
Step 4: Calculate the Sum of Ranks
 Use the
SUM()
function to calculate the total rank for each group.
Example Formula
=SUM(C1:C5) // for Group A
=SUM(D1:D5) // for Group B
Step 5: Calculate U Statistic
The U statistic can be calculated using the following formulas:

For Group A: [ U_A = n_A \times n_B + \frac{n_A \times (n_A + 1)}{2}  R_A ]

For Group B: [ U_B = n_A \times n_B  U_A ]
Where:
 ( n_A ) = number of observations in Group A
 ( n_B ) = number of observations in Group B
 ( R_A ) = sum of ranks for Group A
Step 6: Determine the Significance Level
To find the critical U value, refer to statistical tables or use the NORM.DIST()
function in Excel, which provides probabilities for the normal distribution.
Step 7: Compare the U Statistic to the Critical Value
If the calculated U statistic is less than or equal to the critical value from the tables, you reject the null hypothesis, indicating a significant difference between the two groups. π
Example Calculation
Letβs say you calculated:
 ( U_A = 4 )
 ( U_B = 6 )
Assuming our critical value at a significance level of 0.05 is 4, we have:
 Since ( U_A (4) \leq ) critical value (4), we reject the null hypothesis.
This indicates a significant difference between the two groups. π
Interpreting the Results
Understanding your results is essential for making informed decisions based on your analysis.
Step 8: Make Conclusions π
If you reject the null hypothesis, conclude that there is a significant difference between the two groups. If you fail to reject the null, it suggests there isnβt enough evidence to claim a difference exists.
Summary of the Steps to Perform Mann Whitney U Test in Excel
Step  Action 

1  Organize your data 
2  Rank the data 
3  Calculate sum of ranks 
4  Compute U statistics 
5  Determine critical value 
6  Compare U and make conclusions 
Final Tips and Considerations
 Always visualize your data before running tests. Use box plots or histograms to understand distributions better.
 Ensure that your groups are independent; this is a critical assumption of the Mann Whitney U Test.
 Report your findings clearly, noting the test used, the U statistic, the pvalue, and the significance level.
With this guide, you should be wellequipped to perform the Mann Whitney U Test in Excel. Happy analyzing! π