cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
An alternative to regression  procedure to produce area sample breakdowns of the monthly national estimates of the retail trade survey
Creators: name: Sahai, H.
name: Khurshid, A.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: The paper describes an alternative to regression procedure developed by Woodruff (1966) to produce estimates of geographic subsets of the original population from a national sample. The proposed procedure always produces positive estimates consistent with each other and with the regional and national estimates. The procedure, however, will be less efficient when sample unbiased estimates and corresponding census data are highly correlated. The results are illustrated with a numerical example.
description: Statistica; Vol 55, No 1 (1995)
Towards an understanding of the subjects and the borderlines of today's economic statistics
Creators: name: Cuffaro, M.
name: Davì, M.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: The aim of this paper is to propose a simple novel framework for Economic Statistics. This proposed program is founded on the "core" of the discipline as defined by Zellner: "learning from data and solving practical problems". The program is divided into several arguments referred to the definitions of the macro-aggregates and the interrelations among them, the classification of the economic data and their quality, the use of economic data. For this section it needs referring to real object of Economic Statistics that deals with specific ways of ordering data and testing hypotheses.
description: Statistica; Vol 55, No 1 (1995)
La domanda primaria di caffè in Italia: una analisi statistica
Creators: name: Brasini, S.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: In this paper we estimate the long run economic relationship between ground coffee domestic consumption, advertising expenditure and consumer price during the period 1981-1992. After verifying that all these variables are cointegrated, we make use of a dynamic specification which incorporates an error correction mechanism (ECM). The estimates of the cointegration relationships point out that advertising expenditure doesn't affect coffee consumption level in the short run, while there is causality in both directions between coffee consumption and consumer price with a one month lag. Advertising expenditure has nevertheless a significant effect on consumption level in the long run.
description: Statistica; Vol 55, No 2 (1995)
Derivazione del modello dei valori attesi tramite procedura aggregativa dinamica
Creators: name: Bernini, C.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: The poor capability of the PVM to reproduce the asset price volatility can be due to the representative agent hypothesis. The solution here proposed is based on the microfundation of the PVM. We remove the representative agent hypothesis and define microutility functions, with individual risk aversion coefficient and consumption, which is assumed to be an autoregressive process. By the dynamic aggregation of the microutility functions we obtain an ARMAX model. The new version of PVM, derived from the macroutility function, can take past consumption behaviour into account and allows to use the previsional capability of the ARMAX process. Therefore the PVM can make better forecasts of asset prices and can help to solve the measurement problem of price volatility.
description: Statistica; Vol 55, No 2 (1995)
CARACTERIZACIÓN CINÉTICA Y TERMODINÁMICA DEL HIDRURO COMPLEJO Mg2FeH6
Creators: name: Puszkiel, Julián
name: P. Arneodo Larochette
name: F.C. Gennari
Publisher: name: Zenodo
Year: 2007
Subjects: Hidruros
Almacenamiento
Hidrógeno
Mg-Fe-H

description: El hidruro complejo Mg2FeH6 posee alta capacidad de almacenamiento (5.5 % p/p y 150 Kg H2/ m3) y mejor cinética que el Mg puro. Sin embargo, propiedades como su alta estabilidad y dificultades de síntesis lo convierten en un material no tan apropiado para el almacenamiento, pero mejorable.
 En el presente trabajo se llevó a cabo el estudio de la síntesis, caracterización termodinámica y cinética del hidruro complejo Mg2FeH6.
 El proceso de síntesis del Mg2FeH6 consistió en la molienda mecánica en atmósfera de argón de una mezcla de polvos de composición 2Mg-Fe, seguida de un sinterizado a condiciones de alta presión y temperatura. Las propiedades termodinámicas fueron caracterizadas mediante curvas de presión - composición - temperatura (PCT) de absorción y desorción. A partir de estas mediciones, se construyó el diagrama van’t Hoff y se calcularon los parámetros termodinámicos característicos (entalpía y entropía de descomposición). Los valores termodinámicos obtenidos fueron comparados con los de la literatura. La caracterización cinética consistió en el análisis de la dependencia de la velocidad de absorción y desorción de hidrógeno con la temperatura y el número de ciclos de absorción- desorción.
Sul modo di vincolare la funzione di verosimiglianza quando si è in presenza di informazioni a priori approssimative
Creators: name: Barnabani, M.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: The penalty function method is a mathematical approach generally used in non linear programming and is based on the maximization of a (penalty) function obtained combining linearly through some coefficients called penalty parameters an objective function and the constraints expressed in quadratic form. If the objective function satisfies certain conditions about the continuity, the maximization of the penalty function produces a constrained solution only increasing indefinitely the penalty parameters while for finite values assigned to these parameters we obtain a solution placed between the maximum point and the constrained one. From a statistical viewpoint this approach can be used to constraint a likelihood function when we have prior informations on the parameters of approssimative nature. In this case the particular form (quadratic) of the restraints can be seen as a way to catch all the uncertainty included in this type of prior knowledges and the assigned values to the penalty parameters as a way to quantify this uncertainty.
Statistically the maximization of the likelihood through the penalty function approach emphasizes two problems: the analysis of the property of the estimator produced by this method and the interpretation of the penalty parameter whose value determines the estimates.
In the first case if the usual regularity conditions on the likelihood function are satisfied, the estimator is consistent and asintotically normal whatever is the value of the penalty parameter. In the second case the penalty parameter may be interpreted both as a cost we must pay to depart from the prior informations and as a variance of a stochastic constraint or of a prior distribution. In such a case the penalty function method produces exactly some well known bayesian solutions.
description: Statistica; Vol 55, No 2 (1995)
An almost unbiased iterative ratio-product estimator
Creators: name: Del Mar Rueda, M.
name: Arcos, A.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: In finite population sampling it is common to use information from one or several auxiliary variables through indirect estimators, such as ratio or product estimators. We propose an alternative estimator to the generalized multivariate estimator for cases where several auxiliary variables correlate either positively or negatively with the main variable. This new almost unbiased estimator based on the jackknife technique is always more precise than either the simple expansion estimator (the sample mean) or than the ratio, product, or ratio - product estimators built using any of the available auxiliary variables.
description: Statistica; Vol 55, No 2 (1995)
Universal optimality of nearest  neighbour balanced block designs using ARMA models
Creators: name: Santharam, C.
name: Ponnuswamy, K. N.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: Block designs for observations correlated in one dimension are investigated. Nearest neighbour least balanced designs turnout to be optimal for auto-regressive models when generalized least square estimation is used. Performance of these designs for moving average and ARMA correlation model is shown to be quite satisfactory.
description: Statistica; Vol 55, No 2 (1995)
Recursive nonparamettic estimation of nonlinear systems of Volterra type
Creators: name: Bosq, D.
name: Lessi, O.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: A large class of non linear input-output systems is here represented by means of Volterra series.  These series are completely specified when their coefficients, called Volterra kernels, are known.  Almost sure consistent estimates of Volterra kernels are presented in two fundamental steps.  Firstly the almost sure convergence of a recursive kernel estimator of the joint density of the strongly mixing (or po-dependent) input-output process is obtained.  Secondly the "explosive" behavior of the previous estimator in a neighborhood of the true, input-output functional is established, Volterra kernels are obtained by a projection criterion.  Some simulation results are provided.
description: Statistica; Vol 55, No 3 (1995)
Biometric aspects of woman's menstrual cycle
Creators: name: Alter, P.
name: Monari, P.
name: Montanari, A.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: In this paper we examine some biometric aspects of women's fertile cycle end we statistically test hypothesis concerning the effects of hormone interactions on cycle temporal dynamic.  The data base has been provided by the Catholic Marriage Advisory Council Center (Marshall, 1979) and concerns 31290 cycles (belonging to 1781 women), classified according to their length, the length of pre and postovular phases and woman's age.  The distributional model of cycle and phase lengths has been estimated by a kernel procedure and interesting statistical cause-effect relationships have been highlighted showing a sort of-hormonal balancing action on the physiological process.
description: Statistica; Vol 55, No 3 (1995)
Financial markets and factor structure
Creators: name: Costa, M.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: Testing, in the financial markets, the hypothesis of a k latent factor structure by the methods of exploratory factor analysis rises some difficulties.  In order to get over these problems a new criterion is suggested, in which all a priori known information are used: the sample size and the number of observations.  A Monte Carlo simulation shows that the new criterion performs better than the traditional methods.  Finally, an application to the Italian stock market indicates the presence of a multifactor structure underlying the stock returns.
description: Statistica; Vol 55, No 3 (1995)
Some robustness properties of the Fisher combined test
Creators: name: Pallini, A.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: Robustness of the Fisher combined test is investigated via Lambert's influence function for P-values.  It is well known that this influence function is defined in terms of Bahadur exact slope.  The classical Fisher method of combining independent P-values is asymptotically Bahadur optimal in a reasonable class of combinations of tests.  A robust version for the Fisher combined test is proposed.  This robust test is shown to still have an optimality property in the Bahadur sense.  In particular, it maximizes the Bahadur exact slope in a quite general class of robust Fisher's combinations.
description: Statistica; Vol 55, No 3 (1995)
Analysis of the competitive structure in branded consumer goods markets
Creators: name: Brasini, S.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: In this paper we examine the Italian coffee market competitive structure during the period 1989-1992.  Some market share response functions related to the most important brands are analyzed.  By means of the estimates of an attraction model (Multinornial Logit or MNL) with differential cross-competitive effects we get useful information about the influence of some marketing-mix elements on brands market share.  We can also evaluate the so-called baseline market share.  The results point out that in the short run price is really the most effective marketing instrument for firms which compete in the coffee market.  On the other hand advertising expenditure mainly contributes to brand image reinforcement.
description: Statistica; Vol 55, No 3 (1995)
Estimation of parameters in like-Weibull distribution
Creators: name: Cacciari, M.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: This paper deals with a new method of estimating parameters from a like-Weibull distribution.  The features of these parameters are compared through the failure data of different sample sizes with those of 3-parameter Weibull distribution.
description: Statistica; Vol 55, No 3 (1995)
Depressive Symptom Trajectories and Early Adult Education and Employment: Comparing Longitudinal Cohorts in Canada and the United States
Creators: name: Minh, Anita
name: Bültmann, Ute
name: Reijneveld, Sijmen A.
name: Van Zon, Sander K. R.
name: McLeod, Chris B.
Publisher: name: Multidisciplinary Digital Publishing Institute
Year: 2021

description: Adolescent depressive symptoms are risk factors for lower education and unemployment in early adulthood. This study examines how the course of symptoms from ages 16–25 influences early adult education and employment in Canada and the USA. Using data from the National Longitudinal Survey of Children and Youth (n = 2348) and the National Longitudinal Survey of Youth 79 Child/Young Adult (n = 3961), four trajectories (low-stable; increasing; decreasing; and increasing then decreasing, i.e., mid-peak) were linked to five outcomes (working with a post-secondary degree; a high school degree; no degree; in school; and NEET, i.e., not in employment, education, or training). In both countries, increasing, decreasing, and mid-peak trajectories were associated with higher odds of working with low educational credentials, and/or NEET relative to low-stable trajectories. In Canada, however, all trajectories had a higher predicted probability of either being in school or working with a post-secondary degree than the other outcomes; in the USA, all trajectory groups were most likely to be working with a high school degree. Higher depressive symptom levels at various points between adolescent and adulthood are associated with working with low education and NEET in Canada and the USA, but Canadians are more likely to have better education and employment outcomes.
Outliers sensitivity in EDF goodness-of-fit statistics: an exploratory analysis
Creators: name: Pollice, A.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: This paper deals with the study of the behavior of EDF goodness-of-fit tests in the presence of outliers.  The approach is based on the use of data analytic techniques for analyzing changes in the values of the test statistics caused by extremes observations and groupings in finite dimensional samples.  After developing systematic criteria for defining sets of ideal observations for the stylized representation of continuous distributions (profiles), the behavior of each test statistic is considered when introducing some controlled variations into these samples.  Stylized sensitivity curves and resistance to rejection are obtained for EDF test statistica and used to compare their attitudes towards outlying and grouped observations.
description: Statistica; Vol 55, No 3 (1995)
Uncertainty, entropy and moments problem
Creators: name: Tagliani, Aldo
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: The recovering of a positive density function of which a finite number of moments are assigned is considered from the point of view of maximum entropy approach. The questions concerning the existence, convergence and numerical aspects underlying the practical use of maximum entropy distributions in Statistics are considered. The Hausdorff, Stieltjes and Hamburger momento problem are separately analyzed. The advantages stemming from the use of maximum entropy approach, compared to other approaches, are illustrated.
description: Statistica; Vol 55, No 4 (1995)
Potential Years of Life Lost: a new approach and  an application to a pension scheme
Creators: name: Pasquini, L.
name: Spelta, D.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: In the first part of the paper, after a historical review of the various formulations for the calculation of the P.Y.L.L., we propose an original one, in which the P.Y.L.L. is conditioned to the reaching of a fixed age.  In the second part we utilize the new formula of the P.Y.L.L. within a pension scheme improving the approximation of the solution of the balance equation.  In the last part this new indicator is applied to determine the average monthly contribution paid by an Italian employee in 1991, then the result obtained in this way is compared with those obtained by more traditional formulas.
description: Statistica; Vol 55, No 4 (1995)
Performance of floating stone columns installed in soft soils
Creators: name: Sim, Yu Sheng
Publisher: name: Swinburne
Year: 2024

description: This research focuses on the behaviour of stone columns floating in soft clays in order to determine its serviceability performance. The strength parameters of the column material used in design are often estimated without much technical basis. Therefore, a series of direct shear tests of scalped column materials was conducted to scientifically determine its strength parameters, which were then used in the finite element analyses to benchmark its field performance. The research outcome demonstrates that both the field and FE results show reasonable comparisons, thus validating the design concept and parameters used for the analyses of floating stone columns.
Comparison of correlation coeffìcients when conditional independence constraints between variables are present
Creators: name: Roverato, Alberto
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: Partial correlations are the natural interaction terms to be associated with the edges of the independence graph of a multivariate normal distribution. Two edges of the graph can thus be compared by comparing the corresponding partial correlations.  The comparison of "dependent" correlations is a well known problem in statistics but, when the variables satisfy some conditional independence relations, the maximum likelihood estimates of partial correlations are different from the sample partial correlations, so that classical results no longer bold.  In this paper we analyze to what extent the classical test statistics can be applied.  We show that maximum likelihood estimates of partial correlations are more efficient than sample partial correlations.  Furthermore we show that the conditional independence structure of the model can be used to turn the comparison of "dependent" correlations into the comparison of "independent" parameters.
description: Statistica; Vol 55, No 4 (1995)
Advertising and aggregate consumption in Italy: 1981-1993
Creators: name: Tassinari, Giorgio
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: The paper focuses on the relationship between advertising and aggregate consumption in Italy during the '80s and the first half of the '90s.  Using the Engle and Granger approach for the cointegration analysis and the Granger-Sims test for causality we find non-causality in the long-run but short-run causality from consumption to advertising.  This implies that advertising is pro-cyclical, and that the strong growth of advertising in Italy during the Eighties finds its roots in the rise of oligopolistic competition and in the structural change of the media industry.
description: Statistica; Vol 55, No 4 (1995)
Some notes on bootstrap method for dependent data
Creators: name: Mignani, Stefania
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: Bootstrap method has emerged as a powerful tool for constructing inferential procedures for i.i.d observations.  However, the assumption of having i.i.d. observations is crucial.  It is easily seen that bootstrap gives incorrect answers if dependence is not taken into account.  Two schemes of resampling have been developed.  The first type of methods take resamples from appropriately residuals obtained by fitting a parametric or semiparametric model.  These solutions have been applied with success to ARMA models.  The second type of methods apply resampling to blocks of the original data to keep the dependence structure of data.  The first resampling scheme is based on some model assumptions and therefore is not robust against the violation of the model.  The other type of methods are less model dependent, but the applications is not still automatic.  In this paper we review critically these solutions for dependent data with particularly attention to the blocking methods.
description: Statistica; Vol 55, No 4 (1995)
Determination of the number of factors in the presence of correlated error terms
Creators: name: Cavaliere, Giuseppe
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: The problem of the determination of the number of latent factors is analysed within a generalized factor model, where nonzero elements out of the diagonal of the variance-covariance matrix of error terms are admitted. In this framework, it is proved that classical methods for the selection of the factor model such as likelihood ratio test and information criteria are biased and systematically overestimate the number of factors.  A Monte Carlo experiment shows the different behavior of classical methods and of two alternative criteria which have been developed for the generalized model.
description: Statistica; Vol 55, No 4 (1995)
A systematic review of the latent structure of the Center for Epidemiologic Studies Depression Scale (CES-D) amongst adolescents
Creators: name: Blodgett, Joanna M
name: Lachance, Chantelle C
name: Stubbs, Brendon
name: Co, Melissa
name: Wu, Yu-Tzu
name: Prina, Matthew
name: Tsang, Vivian
name: Cosco, Theodore D.
Publisher: name: BioMed Central
Year: 2021

description: Background: The Centre for Epidemiologic Studies Depression Scale (CES-D) is a commonly used psychometric scale of depression. A four-factor structure (depressed affect, positive affect, somatic symptoms, and interpersonal difficulties) was initially identified in an American sample aged 18 to 65. Despite emerging evidence, a latent structure has not been established in adolescents. This review aimed to investigate the factor structure of the CES-D in adolescents. Methods: We searched Web of Science, PsychINFO and Scopus and included peer-reviewed, original studies assessing the factor structure of the 20-item CES-D in adolescents aged ≤18. Two independent researchers screened results and extracted data. Results: Thirteen studies met the inclusion criteria and were primarily from school-based samples in the USA or Asia. Studies that conducted confirmatory factor analysis (CFA; n = 9) reported a four-factor structure consistent with the original factor structure; these studies were primarily USA-based. Conversely, studies that conducted exploratory factor analysis (EFA) reported distinct two or three factor structures (n = 4) and were primarily based in Asia. Limitations: Studies in a non-English language and those that included individuals aged > 18 years were excluded. Ethnic or cultural differences as well as different analytical methods impacted generalisability of results. The use of CFA as the primary analysis may have biased towards a four-factor structure. Conclusions: A four-factor CES-D structure was an appropriate fit for adolescents in Western countries; further research is required to determine the fit in in Asian countries. This has important implications for clinical use of the scale. Future research should consider how cultural differences shape the experience of depression in adolescents.
Searching for different levels of  households welfare by the fuzzy methodology
Creators: name: Andolina, P.
name: Cuffaro, M.
name: Ficarra, A.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: In this paper, the methodology of fuzzy set is used to analyse the italian Households Budgets of 1992.  Two fuzzy-cluster methods are used: the first one, for searching those variables (the budgets expenses) more representative of the households welfare level and more connected with their social and demographics characteristics; the second one, for clustering the original data in some homogeneous groups of consumption behavior, The results can be related to those of other studies that utilize the standard econometric method of analysis: in particular, a welfare index is identified to form five homogeneous groups of households.
description: Statistica; Vol 55, No 4 (1995)
Calendar methods of fertility regulation: a rule of thumb
Creators: name: Colombo, B.
name: Scarpa, B.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: Suppose that in each menstrual cycle a group of couples abstains for k days from intercourse, otherwise allowed in any other phase of the cycle. In a given cycle, the conception probability will depend on k, on the location within the cycle of the period of abstinence and on the pattern of intercourse episodes. An elaboration of this as-sumption on groups of cycles for which the relevant documentation is available gives idea of its consequences. For each group, under various conditions, an average concep-tion probability in a cycle is estimated. For that purpose, several hypotheses are made: about the size of k; about the location of the period of abstinence within the cycle; about frequency of intercourse outside that phase and the pattern of fecundability on different days of the menstrual cycle. Two fecundability models have been chosen from the literature and the calculations have been made on groups of cycles conveniently selected from a large data base of empirical observations. The results of the exercise give information of some relevance for fertility regulation through the use of calendar methods.
description: Statistica; Vol 56, No 1 (1996)
A general investigation of mean square error matrix superiority in linear regression
Creators: name: Ihorst, G.
name: Trenkler, G.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: Two given generalized ridge estimators of the linear regression model are compared with respect to the matrix mean square error criterion. Using a result concerning the difference of nonnegative definite matrices modified by two matrices of rank one, the investigations by Kawai and Okamoto (1979) and D. Trenkler (1986) are extended to the most general situation of competing estimators.
description: Statistica; Vol 56, No 1 (1996)
Catene di Markov Monte Carlo nei modelli di Ising
Creators: name: Mignani, S.
name: Rosa, R.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: This paper deals with an application of Monte Carlo Markov Chain. This Monte Carlo sampling technique was first introduced by Metropolis et al. to provide estimates of the statistical mechanical Boltzmann averages of parameters of a system of interacting particles. To illustrate an application of this method we have chosen the square spin-flip Ising model, i.e., a regular array of sites with each site occupied by a spin, which is allowed only two orientations. On such a model we have considered estimates of internal energy, magnetization, response functions and relaxation time, at the critical temperature and for different lattice sites. The problem of the accuracy of estimates is discussed in details and it has been shown how the moving block bootstrap can be applied successfully to assess standard errors and to construe confidence intervals for the computed averages. It can been seen also that, when correlation functions have a long-time behaviour, the moving block bootstrap works better than other methods based on subseries values.
description: Statistica; Vol 56, No 1 (1996)
Filter effect in the use of control charts for productive process control
Creators: name: Iacobini, A.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: In this paper  the author analyses the reduction of product nonconformity obtainable through the use of Shewhart control charts during the operative phase of a productive process. This result can be called "filter effect" of control charts. The author supplies a quantification of this effect by defining , in correspondence with a nonconformity input of the process, an approximate measure of the expected proportion of nonconforming units resulting from the use of control charts. The study is conducted both under the classic hypothesis of a single shift,which is constant over time, in the observed process parameter, and under the hypothesis of a uniformly progressive shift. The result obtained show that, at a given level of nonconformity input, the filter effect is more pronounced in the case of a progressive shift, and above all, that it is possible to quantify this effect at assigned levels of risk. It can be observed that the filter effect of a control chart increases when the nonconformity level of the process decreases. Therefore the filter effect is particularly remarkable when more time is needed to detect the process parameter and, consequently, there is a longer exposure to the resulting nonconformity.
description: Statistica; Vol 54, No 1 (1994)
title: The EU Commission and the Fragmentation of International Law
title: Speaking European in a Foreign Land
titleType: Subtitle
Creators: name: Kent, Avidan
Publisher: name: Institut für Völker- und Europarecht, Georg-August-Universität Göttingen
Year: 2016

description: The debate on the fragmentation of International Law has been relatively dormant in recent years. However, recent events demonstrate not only that this debate should be re-awoken, but also that some key elements of this debate must be reconsidered. Notably, while the fragmentation of International Law has often been discussed from the perspective of courts and judges, this article examines the view and the impact of a different institutional actor – the Commission of the European Union. This contribution analyzes a series of amicus briefs that were submitted in a number of investment treaties-based cases. These briefs, which were recently disclosed to the author, reflect a certain radicalization of the European Court of Justice's view concerning the place and the role of the EU's legal system within the international legal order. This article discusses the problematic implications that the Commission's approach may have on the international legal order, as well as possible future pathways.
description: Goettingen Journal of International Law ; Vol. 7, no. 2, page 273-308
Gli indici di proiezione nella Projection Pursuit
Creators: name: Montanari, A.
name: Guglielmi, M.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: In this paper the different measures of non normality, proposed in the statistical literature on projection pursuit as projection indices, are critically reviewed. In order to guarantee an affine invariant final solution, evidence is given for the preferability of affine invariant indices, rather than sphere data. Starting from these considerations, the affine invariant version of each of the presented indices is reported, and the results, obtained on real and simulated data, are compared highlighting the confirmations and the denials towards the ones reported in the literature for sphere data.
description: Statistica; Vol 56, No 1 (1996)
A note on Chakravarty's extended Gini index of income inequality
Creators: name: Michels, S.
name: Ogon, C.
name: Kramer, W.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: We discuss a recent, supposedly transfer sensitive, extension of the Gini-index and show that it does not quite live up to its promises.
description: Statistica; Vol 54, No 2 (1994)
La nozione di spettro stilizzato nell'analisi delle serie storiche
Creators: name: Zoia, M. G.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: This article aims to give a methodological contribution - with considerable operational implications - to economic time series analysis resting on a frequency-domain approach, which finds its roots into Granger's seminal paper (1966). The novelty of the proposal is the introduction of the notion of stylized spectrum, whose estimate reflects the main features of the power distribution of the latent series components over the frequency axis. The stylized spectrum arises transforming the observed series by a battery of filters which  cause a sufficiently]v fine partition of the frequency axis; thus enabling us to detect the power contribution of the frequency ranges corresponding to the components of interest, i.e trend, cyclical and seasonal - possibly evolutive - components. The stylized spectrum estimate is an efficient tool to solve some crucial problems of time series analysis, such as: - setting clear criteria to evaluate the contribution of the latent component to the series dynamics; - comparing the actual performances of alternative procedures of components estimation; - evaluating the definition degree corresponding to different filtering methods, and the relevant accuracy of procedures outcomes.
description: Statistica; Vol 56, No 1 (1996)
On interpreting the imaginary values of Durbin's h-statistic
Creators: name: Dezhbakhsh, H.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: Evidence is provided here that indicates an imaginary value of Durbin's often used h-statistic has no information value in determining the presence or absence of serial correlation in dynamic linear models. However, in many designs an imaginary h value may signal specification problems such as omitted variables or structural shift in coefficients.
description: Statistica; Vol 54, No 2 (1994)
Random non-response on study variable versus on study as well as auxiliary variables
Creators: name: Tracy, D. S.
name: Osahan, S. S.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: In most practical situations in sample surveys, random non-response, for some units, is present on both the study and auxiliary variables. In other situations, it may be present on study variable only since information on the auxiliary variable may be easily obtainable. In this paper, we compare the two situations by considering the usual ratio estimator for the population mean. The former is found to provide a more biased, more efficient and more non-response robust estimator in comparison to the latter whenever it is advisable to use the ratio method of estimation over simple random sampling in the absence of random non-response.
description: Statistica; Vol 54, No 2 (1994)
Identification and estimation of economic time series components: an integrated approach resting on both time and frequency domain arguments
Creators: name: Faliva, M.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: This paper deals with the issues of modeling economic time series and identifying the underlying latent components from both a time and a frequency domain standpoint. Thus, the crucial problem of component estimation is tackled by filter theory arguments.

On the one hand, the band-limited frequency property of the trend-cycle, which ensues from the time domain component characterisation, leads to look at the relevant estimation issue as a low-pass filtering problem. On the other hand, the interpretation of the evolutive mechanism of seasonality as an amplitude modulation process, due to longer period components, suggests the adoption of a detection algorithm for estimation purposes. Moreover, the genuine seasonal pattern is obtained by passing the unmodulated seasonal component through a properly designed wave selector filter and the associated nuisance component enables to estimate the error term as well.  Eventually the whole procedure for estimating the latent components of time series is put into an impressive flow chart.
description: Statistica; Vol 56, No 2 (1996)
Maximum likelihood estimation for Ito processes
Creators: name: Parpinel, F.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: We discuss a general likelihood formula for the estimation of parameters in diffusion processes. The construction of the likelihood is based on the structure exposed by Liptser and Shiryayev. We apply the formula to some linear and non linear models. We consider the possibility of multivariate extensions of the theorem.
description: Statistica; Vol 54, No 2 (1994)
Un metodo dinamico per l'analisi dell'omogeneità non lineare
Creators: name: Tessitore, G.
name: Lauro, N. C.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: Aim of this paper is to propose a new method for Adaptive Fuzzy Homogeneity Analysis. Van Rijckevorsel et al. (1987) define Fuzzy Homogeneity Analysis (FHA) as the Homogeneity analysis of non linear transformed data, where the transformation is performed using B-splines. The originality of the method consists of the inclusion of the knot location among the parameters to be defined and for the adaptivity of the process of optimization of the loss function.  An algorithm to perform the proposed method is described.  A comparison with the results of an exhaustive algorithm is reported to illustrate the performance of the proposed adaptive algorithm.
description: Statistica; Vol 56, No 1 (1996)
Cohen’s method of parameter estimation in truncated normal distribution using moments corrected by quadratic approximation
Creators: name: Akhter, A. S.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: Cohen’s method of moment is applied to estimate the parameters of grouped truncated normal distribution. A quadratic approximation correction method is used to correct the sample moments. This method is sample for equal group intervals, and can also be used for unequal group intervals.
description: Statistica; Vol 56, No 2 (1996)
Pseudo-jackknife estimators for a hyperbinomial process
Creators: name: Ferreri, C.
name: Ferrante, M. R.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: The instability problem of both the maximum likelihood (MLE) and moment method (MME) estimators of the process-index of a hyperbinomial process (HBP) is reconsid-ered coherently with the phenomenical view justifying the choice of the model. Hence, some pseudo-jackknife and graduation procedures are indicated allowing one to attenu-ate instability effects due to both minor fluctuations in the right-tail of a frequency distribution and changes of dispersion type. An example is given in order to illustrate also how the use of the procedures suggested is helpful for making inferences about the process-trend and the process-index functions defining the HBP.
description: Statistica; Vol 56, No 2 (1996)
Estimating random variance option pricing models: an empirical analysis
Creators: name: Pastorello, S.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: This paper deals with the estimation of continuous time stochastic volatility models, which have been introduced in finance to price options on stock and other derivative assets. I start by showing that the indirect inference estimators do not suffer from the bias coming from the approximate discretization of the model, this operation being necessary due to the discrete time frequency of observations. Moreover, I suggest to use observed option prices to estimate the parameters of interest (those of the volatility process) because this avoids a possible mispecification of the drift of the price process. The sample I analyse refers to the CAC 40 index, and it includes 775 daily observations of the price of the index, along with an incomplete panel of corresponding option prices. The results are encouraging, but they also suggest the need of further generalizing both the model and the estimation method.
description: Statistica; Vol 54, No 2 (1994)
A non-parametric method  to analyse basal body temperature dynamics
Creators: name: Capitanio, A.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: In this paper a non-parametric method for the analysis of basal body temperature is proposed. Particularly the proposed technique focuses on the time speed of the studied phenomenon. An empirical application shows how the presented method can be used to identify anomalous cycles.
description: Statistica; Vol 56, No 2 (1996)
Some hints for statistical analysis of vector data
Creators: name: Brizzi, M.
name: Carfagna, E.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: When performing quantitative analysis of some physical phenomena it is sometimes necessary to deal with vector data. This study concerns analytical and graphical repre-sentation of angular data, by mean of an extension of Beta distribution family, as well as spatial analysis of vector variables. Specifically, vector extensions of some well-known spatial interpolation methods are proposed, such as kriging and cokriging.
description: Statistica; Vol 56, No 2 (1996)
Nuptiality and household in Italy. A long period geographical analysis (1861-1881)
Creators: name: Cantisani, G.
name: Dalla Zuanna, G.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: The almost 100 Italian counties are characterised by wide differences concerning both nuptiality and household structure. In this paper these geographical differences are studied, dealing with post-unitary period (1861-1981), using census data. The aim is to underline the most important geographical differences, giving an extensive foundation for the future interpretative research.
Firstly, nuptiality indicators (people never married at age 50 and SMAM of Hajnal, both for males and females) are calculated in the five census years 1881, 1911, 1931, 1961,1981, reconstructing counties boundaries at 1961. This large table is summarised by three principal components analyses (both for males and females and considering together all indicators).
Secondly, territorial differences by household structures are presented, mapping indicators of complex household (proportion of non-nuclear household) in 1881, 1931 and 1981. In 1931 and 1981 indicators are directly calculated by census data, in 1881 counties are ranked by diffusion of non-nuclear household, by an estimation procedure.
Thirdly, connection between geography of nuptiality and household structure are studied in 1881 and 1931, with the aim of checking validity of Laslett and Hajnal framework for Italian situation.
description: Statistica; Vol 56, No 2 (1996)
An alternative device for randomized responses
Creators: name: Singh, S.
name: Singh, R.
name: Mangat, D. S.
name: Tracy, D. S.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: The present study considers an alternate randomization device in unrelated question randomized response model. The proposed model based estimator is unbiased for population proportion and is always more efficient than Greenberg et al. (1969) usual estimator. The conditions under which the proposed model is superior to Mangatts (1991, 1992) recent models have also been obtained.
description: Statistica; Vol 54, No 2 (1994)
A note about mixture models when the mixing density is normal
Creators: name: D'Epifanio, G.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: In this note, we propose a simple, easily implemented procedure to find a local maximize of the likelihood of a general univariate mixture model, assuming that the mixing density is normal, as a possible alternative to the EM procedure.
description: Statistica; Vol 54, No 2 (1994)
The Teaching of Economic Statistics in the Economic Faculties
Creators: name: Quintano, C.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: This work contains a review of some problems affecting the identity of Economic Statistics and other subjects of the same scientific sector and the correlative frontiers linked with the content evolution. The analysis is connected with the reorganisation of the Degree in Economics, particularly with the presence of the subjects included in the group of Economic Statistics in the renewed curricula. Taking into account the results of a scientific Meeting recently organised by prof. Predetti, special attention is devoted by the-Author to the essential requirements of the contents in the subject programs characterising the group of Economic Statistics in relation to the neighbouring branches of learning, to say Methodological Statistics and Econometrics.
description: Statistica; Vol 56, No 2 (1996)
title: The Use of Scholarship by the WTO Appellate Body
Creators: name: Helmersen, Sondre T.
Publisher: name: Institut für Völker- und Europarecht, Georg-August-Universität Göttingen
Year: 2016

description: This article examines the use of scholarship by the WTO Appellate Body. While it is not possible to say definitively how the Appellate Body views the legal status of scholarship in WTO dispute settlement, its use of scholarship will in practice determine its status. The article identifies three overall trends: the Appellate Body's use of scholarship has declined, the Appellate Body uses scholarship mostly for matters of general international law (as opposed to WTO law), and the Appellate body has generally been careful in its use of scholarship. Possible explanations for these trends may include an increase in available precedents, the Appellate Body's specialized role, criticism of the Appellate Body, and its members' backgrounds.
description: Goettingen Journal of International Law ; Vol. 7, no. 2, page 309-351
Distribution of the grammatical forms of the italian language
Creators: name: Rizzi, A.
Publisher: name: Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
Year: 2013

description: In this paper the A. compares the distributions of the grammatical forms (substantives, adjectives, verbs, pronouns, prepositions, conjunctions, etc.) in: "Lessico di frequenza della lingua italiana contemporanea" - Garzanti, 1972 - in "Vocabolario elettronico della lingua italiana" - I.B.M. Italia, 1989 - in "Lessico di frequenza delI'itaIiano parIato" - Etaslibri, 1993 - "Vocabolario di base", published in "Guida all'uso delle parole" - Editori Riuniti, 1992.
description: Statistica; Vol 54, No 3 (1994)