7 citations · 23 across the 22 of their papers we have counts for
10 papers · 1 filter
Closed test procedures for the comparison of dose groups against a negative control group or placebo
Ludwig A. Hothorn
Dose groups are compared with a control assuming an order restriction usually by the Williams trend test. Here, as an alternative, two variants of the closed testing procedure are…
Comparisons of multiple treatment groups with a negative control or placebo group: Dunnett test vs. closed test procedur
Ludwig A. Hothorn
Several treatments are usually compared with a control using the Dunnett test. As an alternative, three variants of the closed testing approach are considered, one with ANOVA-F-tes…
Comparisons of proportions in k dose groups against a negative control assuming order restriction: Williams-type test vs. closed test procedures
Ludwig A. Hothorn
The comparison of proportions is considered in the asymptotic generalized linear model with the odds ratio as effect size. When several doses are compared with a control assuming a…
Statistical evaluation of in-vivo bioassays in regulatory toxicology considering males and females
Ludwig A. Hothorn
The separate evaluation for males and females is the recent standard in in-vivo toxicology for dose or treatment effects using Dunnett tests. The alternative pre-test for sex-by-tr…
Similarity of multiple dose-response curves in interlaboratory studies in regulatory toxicology
Ludwig A. Hothorn, Dimitrios Spiliotopoulos
To claim similarity of multiple dose-response curves in interlaboratory studies in regulatory toxicology is a relevant issue during the assay validation process. Here we demonstrat…
A versatile trend test for the evaluation of tumor incidences in long-term carcinogenicity bioassays
Ludwig A. Hothorn, Atiar M. Rahman, Frank Schaarschmidt
For the evaluation of carcinogenicity bioassays a new trend test is proposed which is based on a maximum of arithmetic, ordinal, and logarithmic regression scores as well as the Wi…
Model-based simultaneous inference for multiple subgroups and multiple endpoints
Charlotte Vogel, Frank Schaarschmidt, Christian Ritz +2
Various methodological options exist on evaluating differences in both subgroups and the overall population. Most desirable is the simultaneous study of multiple endpoints in sever…
Claiming trend in toxicological and pharmacological dose-response studies: an overview on statistical methods and related R-Software
Ludwig A. Hothorn
There are very different statistical methods for demonstrating a trend in pharmacological experiments. Here, the focus is on sparse models with only one parameter to be estimated a…
A Tukey type trend test for repeated carcinogenicity bioassays, motivated by multiple glyphosate studies
Ludwig A. Hothorn, Frank Schaarschmidt
In the last two decades, significant methodological progress to the simultaneous inference of simple and complex randomized designs, particularly proportions as endpoints, occurred…
A modified Armitage test for more than a linear trend on proportions
Ludwig A. Hothorn, Frank Schaarschmidt
The Armitage test for linear trend in proportions can be modified using the multiple marginal model approach for three regression models with arithmetic, ordinal and logarithmic do…