Search results for "statistical"
showing 10 items of 4960 documents
Measuring consumers’ level of satisfaction for online food shopping during COVID-19 in Italy using POSETs
2021
Abstract The pandemic COVID 19 has upset the economic, social, financial, and general behavioral systems. Global crisis has a large impact overall and related fallouts significantly affect existent structural paradigms in every country and region across the world. In particular, the spread of COVID-19 pandemic has led to having to rethink the way we produce and consume food. Within this global change, a rise in the number of consumers who purchase food products online in order to comply with the rules aimed at limiting the circulation of the virus should be emphasized. Consequently, probably causing a long-term positive effect on m-commerce. The purpose is to elaborate on the index of the s…
Inference for Lorenz curve orderings
1999
In this paper we consider the issue of performing statistical inference for Lorenz curve orderings. This involves testing for an ordered relationship in a multivariate context and making comparisons among more than two population distributions. Our approach is to frame the hypotheses of interest as sets of linear inequality constraints on the vector of Lorenz curve ordinates, and apply order-restricted statistical inference to derive test statistics and their sampling distributions. We go on to relate our results to others which have appeared in recent literature, and use Monte Carlo analysis to highlight their respective properties and comparative performances. Finally, we discuss in gener…
Convergence in the OECD: Transitional Dynamics or Narrowing Steady-State Differences?
2004
I. INTRODUCTION Research on growth and convergence has proceeded through several stages that can be described as a process of accommodating cross-country heterogeneity into the convergence equation. In the first stage, the world could be described as countries approaching to equal (absolute convergence) or to different (conditional convergence) steady states. In both cases--see Baumol (1986) Barro and Sala i Martin (1992), or Mankiw et al. (1992)--the assumption of parameter homogeneity of the underlying production function was assumed and not tested. Later, some researchers (Knight et al. [1993], Islam [1995], Durlauf and Johnson [1995], or Caselli et al. [1996], among others) began to cha…
Estimating Engel curves under unit and item nonresponse
2010
SUMMARY This paper estimates food Engel curves using data from the first wave of the Survey on Health, Aging and Retirement in Europe (SHARE). Our statistical model simultaneously takes into account selectivity due to unit and item nonresponse, endogeneity problems, and issues related to flexible specification of the relationship of interest. We estimate both parametric and semiparametric specifications of the model. The parametric specification assumes that the unobservables in the model follow a multivariate Gaussian distribution, while the semiparametric specification avoids distributional assumptions about the unobservables. Copyright © 2011 John Wiley & Sons, Ltd.
Insurance fraud detection: A statistically validated network approach
2022
Fraud is a social phenomenon, and fraudsters often collaborate with other fraudsters, taking on different roles. The challenge for insurance companies is to implement claim assessment and improve fraud detection accuracy. We developed an investigative system based on bipartite networks, highlighting the relationships between subjects and accidents or vehicles and accidents. We formalize filtering rules through probability models and test specific methods to assess the existence of communities in extensive networks and propose new alert metrics for suspicious structures. We apply the methodology to a real database-the Italian Antifraud Integrated Archive-and compare the results to out-of-sam…
"Facta non verba" : an experiment on pledging and giving
2015
International audience; We design an experiment to investigate whether asking people to state how much they will donate to a charity (i.e., to pledge) increases their actual donation. Individuals’ endowment is either certain or a random variable. We study different types of pledges, namely, private, public and irrevocable, which differ in terms of the cost to the individual for not keeping the promise. We show that in absence of endowment uncertainty, private and public pledges are associated with lower donations as compared to donations in the no-pledge case: private pledges slightly reduce donations and public pledges reduce them more significantly. Donations increase with uncertainty (in…
Noise-induced transitions in a stochastic Goodwin-type business cycle model
2017
Abstract We motivate and specify a stochastic Goodwin-type business cycle model. Our analysis focusses on a subset of the parameter space where several attractors coexist. Applying a semi-numerical approach based on the stochastic sensitivity function and confidence domains due to Milstein and Ryashko (1995) , we study random transitions between stable attractors in the context of the Goodwin-type economy embedded in an uncertain environment. Relying on a mix of analytical considerations and simulations we demonstrate that under weak noise levels regime switching is a prominent feature in the presence of low saving rates. Moreover, we explain how increased uncertainty can induce an essentia…
LATVIAN INNOVATION ACTIVITY AND PERSPECTIVES IN THE EU CONTEXT
2013
The new Europe 2020 Strategy for smart, sustainable and inclusive growth has identified innovation as one of the core drivers that can get European countries out of the current economic crisis. The Europe 2020 Strategy sets a 3% of the EU’s GDP to be invested in RD the statistics database of the Central Statistical Bureau of Latvia; Eurostat and other international statistical and methodological materials. Bibliography review, as well as methods of statistical analysis such as grouping, processing and comparative analysis has mainly been used in the paper. DOI: http://dx.doi.org/10.5755/j01.eis.0.7.4119
Biometric analysis of Brachionus plicatilis ecotypes from Spanish lagoons
1983
Univariate comparisons and several multivariate statistical analyses have been performed to study the morphometric variability of B. plicatilis. Both laboratory clones kept under constant conditions and natural populations from different Spanish lagoons and different times of the year have been compared. The results show that not only size, but also allometric coefficients are influenced by environmental factors. However, an important genetic component in the variation of shape and size has been visualized. A clear North-South ordination of the populations of the different lagoons and an important dispersion between their summer populations as well as great differences due to seasonal varia…
Accumuler le capital humain tout au long de la vie: Quels facteurs prédictifs de la participation à la formation permanente?
2003
This article addresses the main predictors of adult education, using statistical methods different from those generally used by social science researchers. Its aim is twofold. First, it seeks to explain in a simple and comprehensible manner the methodological value of these methods (in relation to the use of structural models); secondly, it demonstrates the concrete usefulness of these methods on the basis of a recent piece of research on the data from the International Adult Literacy Survey (IALS).