The issue of the non-invariance of the Wald test under nonlinear reparametrisations of the restrictions under test is studied from a differential geometric viewpoint. Quantities that can be defined in purely geometrical terms are by construction invariant under reparametrisation, and various attempts are made to construct a Wald test out of such invariant quantities only. Despite the existence ...

This paper examines, both theoretically and through Monte Carlo analysis, the implications of applying the HEGY seasonal root tests to a process that is periodically integrated. As an important special case, the random walk process is also considered. In the context of the HEGY regression, the asymptotic distribution of the zero frequency test statistic is dependent on the coefficients of the p...

Spatial scan statistics are widely used for count data to detect geographical disease clusters of high or low incidence, mortality or prevalence and to evaluate their statistical significance. Some data are ordinal or continuous in nature, however, so that it is necessary to dichotomize the data to use a traditional scan statistic for count data. There is then a loss of information and the choi...

We propose a novel approximate-likelihood method to fit demographic models to human genomewide single-nucleotide polymorphism (SNP) data. We divide the genome into windows of constant genetic map width and then tabulate the number of distinct haplotypes and the frequency of the most common haplotype for each window. We summarize the data by the genomewide joint distribution of these two statist...

Genome-wide case-control association study is gaining popularity, thanks to the rapid development of modern genotyping technology. In such studies, population stratification is a potential concern especially when the number of study subjects is large as it can lead to seriously inflated false-positive rates. Current methods addressing this issue are still not completely immune to excess false p...

We develop a new passive imaging method for moving targets in free space using measurements from a sparse array of receivers that rely on illumination sources of opportunity. Our imaging method consists of a novel passive measurement model for moving targets and an associated image formation method. The passive measurement model for moving targets relates measurements at a given receiver to mea...

Rank regression is a highly-efficient and robust approach to estimate regression coefficients and to make inference in the presence of outlying survival times. Heller (2007) developed a smoothed weighted rank regression function, which is used to estimate the regression parameter vector in an accelerated failure time model with right censored data. This function can be expressed as a U -statist...

Functional magnetic resonance imaging (fMRI) is a non-invasive method which can be used to indirectly localize neuronal activations in the human brain. Functional MRI is based on changes in the blood oxygenation level near the activated tissue. In an fMRI experiment, a stimulus is given to a subject or the subject is asked to conduct a physical or cognitive task. During the experiment, a nuclea...