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Steps required in performing the Wilcoxon rank sum (Mann–Whitney) test |
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| Step |
Details |
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| 1 |
Rank all observations in increasing order of magnitude, ignoring which group they come from. If two observations have the same magnitude, regardless of group, then they are given an average ranking |
| 2 |
Add up the ranks in the smaller of the two groups (S). If the two groups are of equal size then either one can be chosen |
| 3 |
Calculate an appropriate P value |
Whitley and Ball Critical Care 2002 6:509 doi:10.1186/cc1820 |
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