This article investigates power and size of some tests for exogeneity of a binary explanatory variable in count models by conducting extensive Monte Carlo simulations. The tests under consideration are Hausman contrast tests as well as univariate Wald tests, including a new test of notably easy implementation. Performance of the tests is explored under misspecification of the underlying model a...

BACKGROUND Social attitudes toward male homosexuality in China so far are still not optimistic. Sexual minorities in China have reported high levels of internalized homophobia. METHODS This Internet-based study examined the associations among internalized homophobia, mental health, sexual behaviors, and outness among 435 gay/bisexual men in Southwest China from 2014 to 2015. Latent profile an...

BACKGROUND Detection of risk factors for an air embolism in the left atrium, left ventricle, or systemic circulation (systemic air embolism, SAE) during a percutaneous core needle biopsy (PCNB) of the thorax. METHODS In a retrospective observational study, all PCNBs of the thorax in 610 patients between 2007 and 2009 were analyzed. The SmartStep™ technique (General Electric) was used for the ...

BACKGROUND A two-arm non-inferiority trial without a placebo is usually adopted to demonstrate that an experimental treatment is not worse than a reference treatment by a small pre-specified non-inferiority margin due to ethical concerns. Selection of the non-inferiority margin and establishment of assay sensitivity are two major issues in the design, analysis and interpretation for two-arm non...

This paper develops Wald type tests for general possibly nonlinear restrictions, in the context of heteroskedastic IV regression with many weak instruments. In particular, it is first shown that consistency and asymptotically normality can be obtained when estimating structural parameters using JIVE, even when errors exhibit heteroskedasticity of unkown form. This is not the case, however, with...

Johnson, S. (1996). Down’s syndrome screening in the UK, Lancet, 347, 906–907. Pandya, P.P., Snijders, R.J.M., Johnson, S.P., de Loudes Brizot, M., Nicolaides, K.H. (1995). Screening for fetal trisomies by maternal age and fetal nuchal translucency thickness at 10 to 14 weeks of gestation, Br. J. Obstet. Gynaecol., 102, 957–962. Schuchter, K., Wald, N.J., Hackshaw, A.K., Hafner, E., Liebhardt, ...

Mit dem Waldmanagementsystem „Virtueller Wald“1 (www.virtuellerwald.net) gehen die sprichwörtlichen Zeiten, in denen man den Wald vor lauter Bäumen nicht sehen konnte, dem Ende entgegen. Grundlage hierfür ist eine flächendeckende, qualitativ hochwertige, aktuelle, auswertbare georeferenzierte Waldinventur, die mit Unterstützung leistungsfähiger Sensordaten verarbeitender Algorithmen auf der Bas...

In personalized medicine, two important tasks are predicting disease risk and selecting appropriate treatments for individuals based on their baseline information. The dissertation focuses on providing improved risk prediction for ordinal outcome data and proposing score-based test to identify informative markers for treatment selection. In Chapter 1, we take up the first problem and propose a ...

We evaluate by simulation three model-based methods to test the influence of a single nucleotide polymorphism on a pharmacokinetic parameter of a drug: ANOVA on the empirical Bayes estimates of the individual parameters, likelihood ratio test between models with and without genetic covariate, and Wald tests on the parameters of the model with covariate. Analyses are performed using the FO and F...