How to do the test:

- State your Null Hypothesis in the form:

"There is no difference between the populations from which two unrelated samples come" - Choose a Critical Significance Level (α: alpha)

This is typically α = 0.05 - Calculate the statistic

Use a spreadsheet to calculate your results,**or**

Access a helpsheet for SPSS

and check here for data entry into SPSS - Reject or accept your Null Hypothesis

**Either**compare the calculated statistic with Critical Value,

NOTE: The calculation yields two values of the U statistic. Either can be used, but both the spreadsheet and SPSS use the**smaller**value. Thus:

If U ≤ U_{critical}→ reject H_{0}→ significant result

If U > U_{critical}→ accept H_{0}→ non-significant result

**or**

Look at the calculated probability (*P*value)

If*P*≤ α → reject H_{0}→ significant result

If*P*> α → accept H_{0}→ non-significant result - Report your results

Plot your data using the appropriate graphs

(Mann-Whitney U test: U = …,*n*_{1}= …,*n*_{2}= …,*P*= …)

View an example report