Search results for "statistical"

Entropy

2008

Testing alternative vicariance scenarios in Western Mediterranean discoglossid frogs

2004

Dated molecular phylogenies are often used to interpret evolutionary history with respect to paleogeographic events. Where more than one interpretation is possible, it is desirable but difficult to assess the alternatives in an objective manner. The present work demonstrates a formalized method for testing molecular clock calibrations and biogeographic scenarios based on them. We assessed the plausibility of several previously published biogeographic hypotheses, using the frog genera Alytes, Discoglossus, and Bombina as model groups. Our data set comprised ca. 900bp of partial mitochondrial 16S and 12S rRNA gene sequences (both genes evolved in a clock-like manner across genera) from nearly…

Polarization and suburbanisation in Warsaw

2001

The economic transition in Poland leads to a restructuration of economic activities which affects spatial patterns of cities, especially in Warsaw. Analyzing the location and re-location of population and employment in Poland’s capital allows to enlarge the debate on the suburbanization forms to the Central and Oriental European Countries. The results support the fact that the city center is still largely the most important district in terms of population andemployment, so that in 1999 the city keeps a strong monocentric character. However, from 1994 to 1999, population and employment move towards the Warsaw’s suburbs. Two significant observations, namely the suburbanization of retailing an…

Third Sector, Social Enterprises and Local Authorities in a EU Candidate Country. The Case of Albania

2013

The paper is based on evidence offered by survey data collected through a structured questionnaire in a long range survey launched in July 2012 by the Steering Group of ASE Forum. The aim of the study was to reveal the trend, status, profile, features and the role of potentials enterprises in Albania in supporting welfare and wellbeing in synergy with the local authorities.After an appropriate methodological introduction, the paper reports main statistical evidence concerning the Third sector in Albania and the direct survey outcomes about the features and the activity of the organizations interviewed.Conclusions will be driven by data analysis and will be focused on the needs, limits and o…

Quantitative Characteristics of Information Society and ICT Industry in Latvia

2015

Abstract The article is devoted to statistical analysis of information and communication technology (ICT) industry in Latvia and the development of Information Society in the country. On the basis of statistical data comparison of Latvia with other European countries is made. This comparison shows that Latvia belongs to countries with very well developed Internet. On the other hand the statistical data points on the fact that it is necessary to increase the awareness of population regarding possibilities offered by using of ICT and e-Government.

Dealing with preference uncertainty in contingent willingness to pay for a nature protection program: A new approach

2013

In this paper, we propose an alternative preference uncertainty measurement approach where respondents have the option to indicate their willingness to pay (WTP) for a nature protection program either as exact values or intervals from a payment card, depending on whether they are uncertain about their valuation. On the basis of their responses, we then estimate their degree of uncertainty. New within this study is that the respondent's degree of uncertainty is "revealed", while it is "stated" in those using existing measurement methods. Three statistical models are used to explore the sources of respondent uncertainty. We also present a simple way of calculating the uncertainty adjusted mea…

Networked relationships in the e-MID Interbank market: A trading model with memory

2014

Interbank markets are fundamental for bank liquidity management. In this paper, we introduce a model of interbank trading with memory. Our model reproduces features of preferential trading patterns in the e-MID market recently empirically observed through the method of statistically validated networks. The memory mechanism is used to introduce a proxy of trust in the model. The key idea is that a lender, having lent many times to a borrower in the past, is more likely to lend to that borrower again in the future than to other borrowers, with which the lender has never (or has in- frequently) interacted. The core of the model depends on only one parameter representing the initial attractiven…

Do firms share the same functional form of their growth rate distribution? A statistical test

2014

We introduce a new statistical test of the hypothesis that a balanced panel of firms have the same growth rate distribution or, more generally, that they share the same functional form of growth rate distribution. We applied the test to European Union and US publicly quoted manufacturing firms data, considering functional forms belonging to the Subbotin family of distributions. While our hypotheses are rejected for the vast majority of sets at the sector level, we cannot rejected them at the subsector level, indicating that homogenous panels of firms could be described by a common functional form of growth rate distribution.

Variable selection in the analysis of energy consumption-growth nexus

2015

There is abundant empirical literature that focuses on whether energy consumption is a critical driver of economic growth. The evolution of this literature has largely consisted of attempts to solve the problems and answer the criticisms arising from earlier studies. One of the most common criticisms is that previous work concentrates on the bivariate relationship, energy consumption–economic growth. Many authors try to overcome this critique using control variables. However, the choice of these variables has been ad hoc, made according to the subjective economic rationale of the authors. Our contribution to this literature is to apply a robust probabilistic model to select the explanatory …

The effect of round-off error on long memory processes

2011

We study how the round-off (or discretization) error changes the statistical properties of a Gaussian long memory process. We show that the autocovariance and the spectral density of the discretized process are asymptotically rescaled by a factor smaller than one, and we compute exactly this scaling factor. Consequently, we find that the discretized process is also long memory with the same Hurst exponent as the original process. We consider the properties of two estimators of the Hurst exponent, namely the local Whittle (LW) estimator and the Detrended Fluctuation Analysis (DFA). By using analytical considerations and numerical simulations we show that, in presence of round-off error, both…