Mann-Whitney Test (Non-parametric)
What Is It?
A Mann-Whitney test is used when you have a small sample size and equivalent to a 2 sample t-test. It is used when you don't feel that you can assume that the data comes from a normal distribution (so especially relevant for ordinal datasets). It is used to test differences in the medians of the populations.
How Do You Carry One Out In SPSS?
For the purposes of this illustration we are going to assume that we are testing 2 different groups (Group 1 and Group 2) of independent data against a dependent variable.
Once you have entered your data into SPSS you need to go do ANALYSE > NONPARAMETRIC TESTS > LEGACY DIALOGS > 2 INDEPENDENT SAMPLES. This will bring up the Two Independent Samples Test dialogue box which should show your 2 datasets in the left hand box. Firstly you need to check that Mann-Whitney U is ticked at the bottom of the dialogue, not any of the other tests.
Next you take your dependent variable and move it into the Test Variable List: box on the right hand side of the dialogue box, and then move your independent variable into the Grouping Variable: box which is just below the Test Variable List: box. Once that is done click Define Groups and it will ask you to define Group 1 and Group 2. Put a 1 into Group 1 and a 2 into Group 2 and click Continue.
A final dialogue box will appear presenting some other options for the test results (like would you like quartiles) which aren't Mann-Whitney related and then you can click Continue to run the test.
What Is It?
A Mann-Whitney test is used when you have a small sample size and equivalent to a 2 sample t-test. It is used when you don't feel that you can assume that the data comes from a normal distribution (so especially relevant for ordinal datasets). It is used to test differences in the medians of the populations.
How Do You Carry One Out In SPSS?
For the purposes of this illustration we are going to assume that we are testing 2 different groups (Group 1 and Group 2) of independent data against a dependent variable.
Once you have entered your data into SPSS you need to go do ANALYSE > NONPARAMETRIC TESTS > LEGACY DIALOGS > 2 INDEPENDENT SAMPLES. This will bring up the Two Independent Samples Test dialogue box which should show your 2 datasets in the left hand box. Firstly you need to check that Mann-Whitney U is ticked at the bottom of the dialogue, not any of the other tests.
Next you take your dependent variable and move it into the Test Variable List: box on the right hand side of the dialogue box, and then move your independent variable into the Grouping Variable: box which is just below the Test Variable List: box. Once that is done click Define Groups and it will ask you to define Group 1 and Group 2. Put a 1 into Group 1 and a 2 into Group 2 and click Continue.
A final dialogue box will appear presenting some other options for the test results (like would you like quartiles) which aren't Mann-Whitney related and then you can click Continue to run the test.
