Approximating the power of Wilcoxon's rank-sum test against shift alternatives
✍ Scribed by James F. Troendle
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 151 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0277-6715
No coin nor oath required. For personal study only.
✦ Synopsis
Three methods of approximating the power of Wilcoxon's rank-sum test against shift alternatives are studied. They are obtained by using a Gaussian assumption, Edgeworth expansion, or bootstrap. It is assumed that a historical data set is available to use in estimating the shape of the distribution. The methods are compared through simulation across several di!erent distributional types. The results indicate that the bootstrap generally gives the most reliable approximation, however the Edgeworth expansion has the practical advantage that a lower bound on the power can be roughly approximated. The methods are illustrated on muscle strength data from patients with osteogenesis imperfecta.