❝ ❝ […] In a 2*2 cross-over BE study. If we want to test the Tmax betweent different treatments. Which test statistic should be used? Wilcoxon signed rank test or Wilcoxon rank sum test?
❝ The former (aka Wilcoxon T test).
❝ The latter (aka Mann–Whitney U test, Mann–Whitney–Wilcoxon test, Wilcoxon–Mann–Whitney test) is for independent samples (parallel design).
Here you err!
The Wilcoxon signed rank test1 can only applied if you neglect period effects. It tests the within-subject treatment differences against zero and is therefore a non-parametric analogon of the paired Student t-test.
To account for period effects you have to apply the Wilcoxon–Mann–Whitney test2 with sequence as grouping factor if you evaluate a 2x2 cross-over design. This test is sometimes also called Hauschke test. Guess why .
In case of a parallel design the grouping factor is of course the treatment, as you correctly stated.
The cited example you quote uses the correct test.
And I suppose Phoenix 8.0 / Crossover object does the same
1 V. W. Steinijans and E. Diletti
"Statistical Analysis of Bioavailability Studies: Parametric and Nonparametric Confidence Intervals"
Eur J Clin Pharmacol (1983) 24:127-136
2 D. HAUSCHKE, V. W. STEINIJANS and E. DILETTI
"A distribution-free procedure for the statistical analysis of bioequivalence studies"
International Journal of Clinical Pharmacology, Therapy and Toxicology,
Vol. 28 No. 2 -1990 (72-78) / Vol.30, Suppl. No. 1 -1992 (pp,S37-43)
- Test statistic about Tmax libaiyi 2018-06-19 08:15 [Nonparametrics]
- Wilcoxon signed rank test Helmut 2018-06-19 11:54