Mann-Whitney U test for Subgroups 1 and 2 (generated in IBM SPSS Statistics 19)
| Ranks | ||||
|---|---|---|---|---|
| Subgroup No. | N | Mean Rank | Sum of Ranks | |
| ODI | 1.00 | 20 | 21.93 | 438.50 |
| 2.00 | 16 | 14.22 | 227.50 | |
| Total | 36 | |||
| SSS | 1.00 | 20 | 21.80 | 436.00 |
| 2.00 | 16 | 14.38 | 230.00 | |
| Total | 36 | |||
| mCS | 1.00 | 20 | 10.50 | 210.00 |
| 2.00 | 16 | 28.50 | 456.00 | |
| Total | 36 | |||
| Test Statisticsq | ||||
| ODI | SSS | mCS | ||
| Mann-Whitney U | 91.50 | 94.00 | 000 | |
| Wilcoxon W | 227.500 | 230.000 | 210.000 | |
| Z | -2.191 | -2.108 | -5.116 | |
| Asymp. Sig (2-tailed) | .028 | .035 | .000 | |
↵a Grouping Variable: Subgroup Number
ODI – Oswestry Disability Index. SSQ – Swiss Spinal Stenosis Questionnaire. mCS – Mean Coefficient of Stenosis.