Search results for "Inference"
showing 10 items of 478 documents
Automatic regrouping of strata in the goodness-of-fit chi-square test
2019
Pearson’s chi-square test is widely employed in social and health sciences to analyze categorical data and contingency tables. For the test to be valid, the sample size must be large enough to provide a minimum number of expected elements per category. This paper develops functions for regrouping strata automatically no matter where they are located, thus enabling the goodness-of-fit test to be performed within an iterative procedure. The functions are written in Excel VBA (Visual Basic for Applications) and in Mathematica. The usefulness and performance of these functions is illustrated by means of a simulation study and the application to different datasets. Finally, the iterative use of …
Inference for the interclass correlation in familial data using small sample asymptotics
2012
Inference on the parent-offspring correlation coefficient is an important problem in the analysis of familial data, and point estimates and likelihood based inference are available in the literature. In this work, corrections for the signed log-likelihood ratio test statistics are proposed, based on small sample asymptotics, in order to achieve accurate small sample performance. The corrected statistic can be used for hypothesis testing as well as for interval estimation.
Finite Sample Sizes of the GRS Test in the Presence of Dynamic Correlation and Conditional Heteroskedasticity
2017
This paper investigates the finite sample properties of the widely-used Gibbons, Ross, Shanken (1989) (GRS) test in the presence of both conditional correlation and conditional heteroskedasticity. It finds that the GRS test exhibits serious size distortions resulting in potentially misleading statistical inferences. The correct critical values, as reported in the study, are considerably larger than suggested by the GRS test.
Convergence of Agents' and Targets' Reports on Intraorganizational Influence Attempts1
2003
Summary The object of the current study was to determine the convergent and discriminant validity of agents' and targets' reports on intraorganizational influence attempts with a structural equation model using latent state-trait analyses. To explain agent-target convergence, we linked the theory of formal organizations to Correspondent Inference Theory. Managers (agents) were asked to describe how they try to influence their boss, a coworker, and a subordinate. These targets also described how the agent tries to influence them. Both agents and targets rated four types of influence attempts twice within 2½ months, namely, rational persuasion, ingratiation, pressure, and upward appeals. In …
Morphostatistical characterization of the spatial galaxy distribution through Gibbs point processes
2021
This paper proposes a morpho-statistical characterisation of the galaxy distribution through spatial statistical modelling based on inhomogeneous Gibbs point processes. The galaxy distribution is supposed to exhibit two components. The first one is related to the major geometrical features exhibited by the observed galaxy field, here, its corresponding filamentary pattern. The second one is related to the interactions exhibited by the galaxies. Gibbs point processes are statistical models able to integrate these two aspects in a probability density, controlled by some parameters. Several such models are fitted to real observational data via the ABC Shadow algorithm. This algorithm provides …
Causal Inference and Statistical Fallacies
2001
Fallacies are defined as plausible-seeming arguments that give the wrong conclusion. The article concentrates on those with some connection with causality. The classical definition of causality involving a necessary and sufficient condition for an effect is rejected and three possible definitions discussed. The first is that of a statistical association that cannot be explained away as the effect of admissible alternative features. To make this more precise, Markov graphical representations are introduced and the important distinction between pairs of variables on an equal footing and those in a potential explanatory-response relation described. The roles of unobserved confounders and of ra…
Storytelling and story testing in domestication
2014
The domestication of plants and animals marks one of the most significant transitions in human, and indeed global, history. Traditionally, study of the domestication process was the exclusive domain of archaeologists and agricultural scientists; today it is an increasingly multidisciplinary enterprise that has come to involve the skills of evolutionary biologists and geneticists. Although the application of new information sources and methodologies has dramatically transformed our ability to study and understand domestication, it has also generated increasingly large and complex datasets, the interpretation of which is not straightforward. In particular, challenges of equifinality, evolutio…
On Conditions Instantiating Tip Effects of Epistemic and Evidential Meanings in Bulgarian
2012
Статья посвящена условиям, при которых происходит попеременная актуализация то эвиденциального, то эпистемического компонента в семантическом потенциале эвиденциальных показателей болгарского языка. Сосредоточиваясь на сентенциальных наречиях с инферентивными функциями, мы опираемся на следующие предпосылки: (i) для каждой единицы следует отличать её устойчивое семантическое значение от прагматического потенциала, выявлению которого способствуют (или препятствуют) те или иные коммуникативные условия; (ii) эвиденциальные и эпистемические компоненты значения довольно легко вытесняют друг друга из позиции доминанты, причём процесс подавления то одного, то другого компонента обусловлен действие…
The role of blood DNA methylation in environment-related chronic disease: a biostatistical toolkit
2013
La epigenética se refiere al estudio de las marcas químicas que alteran la expresión génica sin cambiar la secuencia genética. Los factores ambientales y conductuales son conocidos modificadores de la epigenética, resultando así en cambios heredables que pueden dar lugar a alteraciones en procesos biológicos esenciales y, por consiguiente, al desarrollo de enfermedades. La metilación del ADN es la marca epigenética más estudiada. Existe amplia evidencia científica de la asociación entre factores ambientales tales como tabaco y metales, y desregulaciones en la metilación del ADN. Asimismo, existe amplia evidencia de la asociación entre desregulaciones en metilación del ADN y enfermedades cró…
Network reconstruction for trans acting genetic loci using multi-omics data and prior information.
2022
Background: Molecular measurements of the genome, the transcriptome, and the epigenome, often termed multi-omics data, provide an in-depth view on biological systems and their integration is crucial for gaining insights in complex regulatory processes. These data can be used to explain disease related genetic variants by linking them to intermediate molecular traits (quantitative trait loci, QTL). Molecular networks regulating cellular processes leave footprints in QTL results as so-called trans-QTL hotspots. Reconstructing these networks is a complex endeavor and use of biological prior information can improve network inference. However, previous efforts were limited in the types of priors…