-
作者：Larsen, PV; Blæsild, P; Sorensen, MK
作者单位：University of Southern Denmark; Aarhus University
摘要：Explicit expressions for the directed likelihood statistic, r, and two modified directed likelihood statistics, r* and r(dagger), are given for several standard hypotheses on concentrations in von Mises-Fisher distributions, and for several standard hypotheses on mean directions in von Mises distributions.
-
作者：Scharfstein, DO; Robins, JM
作者单位：Johns Hopkins University; Johns Hopkins Bloomberg School of Public Health; Harvard University; Harvard T.H. Chan School of Public Health
摘要：We present a method for estimating the survival curve of a continuous failure time random variable from right-censored data. Our method allows adjustment for informative censoring due to measured prognostic factors for time-to-event and censoring while simultaneously quantifying the sensitivity of the inference to residual dependence between failure and censoring due to unmeasured factors. We present the results of a simulation study and illustrate our approach using data from the AIDS Clinica...
-
作者：Hettmansperger, TP; Randles, RH
作者单位：Pennsylvania Commonwealth System of Higher Education (PCSHE); Pennsylvania State University; Pennsylvania State University - University Park; State University System of Florida; University of Florida
摘要：A robust affine equivariant estimator of location for multivariate data is proposed which becomes the univariate median for data of dimension one. The estimator is robust in the sense that it has a bounded influence function, a positive breakdown value and has high efficiency compared to the sample mean for heavy-tailed distributions. Perhaps its greatest strength is that, unlike other affine equivariant multivariate medians, it is easily computed for data in any practical dimension.
-
作者：Barber, S; Jennison, C
作者单位：University of Bristol; University of Bath
摘要：We extend the optimal symmetric group sequential tests of Eales & Jennison (1992) to the broader class of asymmetric designs. Two forms of asymmetry are considered, involving unequal type I and type II error rates and different emphases on expected sample sizes at the null and alternative hypotheses. We discuss the properties of our optimal designs and use them to assess the efficiency of the family of tests proposed by Pampallona & Tsiatis (1994) and two families of one-sided tests defined th...
-
作者：DiCiccio, TJ; Monti, AC
作者单位：Cornell University; University of Sannio
摘要：This paper concerns high-order inference for scalar parameters that are estimated by functions of multivariate M-estimators. Asymptotic formulae for the bias and skewness of the studentised statistic are derived. Although these formulae appear complicated, they can be evaluated easily by using matrix operations and numerical differentiation. Various methods for constructing second-order accurate confidence limits are discussed, including a method based on skewness-reducing transformations and ...
-
作者：Pérez, JM; Berger, JO
作者单位：Simon Bolivar University; Duke University
摘要：We consider the problem of comparing parametric models using a Bayesian approach. A new method of developing prior distributions for the model parameters is presented, called the expected-posterior prior approach. The idea is to define the priors for all models from a common underlying predictive distribution, in such a way that the resulting priors are amenable to modern Markov chain Monte Carlo computational techniques, The approach has subjective Bayesian and default Bayesian implementation...
