Search results for "hypothesis testing"
showing 10 items of 124 documents
Empirical model evaluation and hypothesis testing
2016
Chapter 5 deals with the empirical model evaluation and the testing of hypotheses. It starts out with the evaluation of the measurement and the structural models, using the PLS algorithm. After the evaluation of the complete model, moderating effects are examined by conducting group comparisons (section 5.4.1) and by investigating interaction effects (5.4.2). After that, selected constructs are further examined by exploratory data analysis (section 5.5).
Random Interruptions in Cooperation for Spectrum Sensing in Cognitive Radio Networks
2015
In this paper, a new cooperation structure for spectrum sensing in cognitive radio networks is proposed which outperforms the existing commonly-used ones in terms of energy efficiency. The efficiency is achieved in the proposed design by introducing random interruptions in the cooperation process between the sensing nodes and the fusion center, along with a compensation process at the fusion center. Regarding the hypothesis testing problem concerned, first, the proposed system behavior is thoroughly analyzed and its associated likelihood-ratio test (LRT) is provided. Next, based on a general linear fusion rule, statistics of the global test summary are derived and the sensing quality is cha…
The Max-Product Algorithm Viewed as Linear Data-Fusion: A Distributed Detection Scenario
2019
In this paper, we disclose the statistical behavior of the max-product algorithm configured to solve a maximum a posteriori (MAP) estimation problem in a network of distributed agents. Specifically, we first build a distributed hypothesis test conducted by a max-product iteration over a binary-valued pairwise Markov random field and show that the decision variables obtained are linear combinations of the local log-likelihood ratios observed in the network. Then, we use these linear combinations to formulate the system performance in terms of the false-alarm and detection probabilities. Our findings indicate that, in the hypothesis test concerned, the optimal performance of the max-product a…
General framework for testing Poisson-Voronoi assumption for real microstructures
2020
Modeling microstructures is an interesting problem not just in Materials Science but also in Mathematics and Statistics. The most basic model for steel microstructure is the Poisson-Voronoi diagram. It has mathematically attractive properties and it has been used in the approximation of single phase steel microstructures. The aim of this paper is to develop methods that can be used to test whether a real steel microstructure can be approximated by such a model. Therefore, a general framework for testing the Poisson-Voronoi assumption based on images of 2D sections of real metals is set out. Following two different approaches, according to the use or not of periodic boundary conditions, thre…
Can visualization alleviate dichotomous thinking? Effects of visual representations on the cliff effect
2021
Common reporting styles for statistical results in scientific articles, such as $p$ p -values and confidence intervals (CI), have been reported to be prone to dichotomous interpretations, especially with respect to the null hypothesis significance testing framework. For example when the $p$ p -value is small enough or the CIs of the mean effects of a studied drug and a placebo are not overlapping, scientists tend to claim significant differences while often disregarding the magnitudes and absolute differences in the effect sizes. This type of reasoning has been shown to be potentially harmful to science. Techniques relying on the visual estimation of the strength of evidence have been recom…
Educación XX1 : revista de la Facultad de Educación
2017
Introducción: La institucionalización del Aprendizaje-Servicio (ApS) en la universidad recomienda, en primer lugar, el análisis de la cultura docente del profesorado y su actitud hacia la innovación. Precisamente, lo que este trabajo pretende es aportar un modelo teórico integrador desarrollando tres escalas de evaluación, contrastadas a través de pruebas estadísticas, para el contexto de la enseñanza universitaria en España. Metodología: A fin de elaborar el modelo de medida se aplicaron tres escalas a 1903 profesoras y profesores de 6 universidades españolas: una escala de práctica docente (18 ítems), otra sobre compromiso social de la Universidad (9 ítems), y una tercera, sobre prácticas…
Empirical Analyses of Networks in Finance
2018
Abstract The recent global financial crisis has triggered a huge interest in the use of network concepts and network tools to better understand how instabilities can propagate through the financial system. The literature is today quite vast, covering both theoretical and empirical aspects. This review concentrates on empirical work, and associated methodologies, concerned with the evaluation of the fragility and resilience of financial and credit markets. The first part of the review examines the literature on systemic risk that arise from banks mutual exposures. These exposures stem primarily from interbank lending and derivative positions, but also, indirectly, from common holdings of oth…
Modeling the Dynamics of a Financial Index after a Crash
2004
Supply and demand are perhaps the most fundamental concepts in economics. In a financial market they reflects the orders of the agents to buy or sell a given asset. In turn the fluctuations of supply and demand influence the dynamics of the price of an asset, as, for example, a stock or a financial index. Therefore the dynamics of the price of an asset is affected by the actions and of the beliefs of the agents. It is known that the dynamics of the price of an asset is far from simple, Several stylized facts has been empirically discovered such as, for example, the fat tails in the return distribution and the clustered volatility. These stylized facts has been detected by considering long t…
Content quality assessment and acceptance testing in location‐based services
2006
In this paper, we develop and evaluate an approach to assessing the content quality in a location‐based service (LBS). The proposed approach, instead of assessing the quality in absolute terms such as completeness or accuracy, measures the effect that the imperfection of the content is having on the reliability of that specific LBS. We apply the basic ideas from Software Reliability Engineering (SRE), but develop a modification of SRE, 2‐Branch, in order to separate content quality from other factors, such as positioning imprecision, and to reduce the measurement error. In our experimental study, we first compare 2‐Branch to the standard SRE, after which we experimentally analyze some prope…
Empirical Likelihood-Based ANOVA for Trimmed Means
2016
In this paper, we introduce an alternative to Yuen’s test for the comparison of several population trimmed means. This nonparametric ANOVA type test is based on the empirical likelihood (EL) approach and extends the results for one population trimmed mean from Qin and Tsao (2002). The results of our simulation study indicate that for skewed distributions, with and without variance heterogeneity, Yuen’s test performs better than the new EL ANOVA test for trimmed means with respect to control over the probability of a type I error. This finding is in contrast with our simulation results for the comparison of means, where the EL ANOVA test for means performs better than Welch’s heteroscedastic…