|
Relative power of t-test and Mann-Whitney given as relative efficiency. Values less than 1 indicate greater power of t-test; greater than 1 indicates superiority of Mann-Whitney. Results are combined across sample sizes and correlations. |
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| Distribution |
Post-treatment scores |
Change scores |
|
|
||
| Moderate positive skew: shift |
0.9348 |
0.9835 |
| Moderate positive skew: ratio |
1.1382 |
1.0436 |
| Moderate negative skew: shift |
1.1833 |
1.0187 |
| Moderate negative skew: ratio |
0.9301 |
0.9825 |
| Uniform: shift |
0.9339 |
0.9846 |
| Uniform: ratio |
0.9488 |
0.9929 |
| Extreme negative skew: shift |
1.3769 |
1.1140 |
| Extreme negative skew: ratio |
1.6675 |
1.2046 |
| Extreme asymmetry: shift |
7.1461 |
0.5370 |
| Extreme asymmetry: ratio |
9.0091 |
0.6432 |
| Normal: shift |
0.9660 |
0.9726 |
| Normal: ratio |
0.9740 |
0.9760 |
Vickers BMC Medical Research Methodology 2005 5:35 doi:10.1186/1471-2288-5-35 |
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