Full-text resources of CEJSH and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl

Results found: 7

first rewind previous Page / 1 next fast forward last

Search results

Search:
in the keywords:  Econometric modeling
help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
EN
The methods for analyzing cross-classified tables are usually to test relations between two variables taken one pair at a time. Further development of those methods allowed to move from two dimensional tables to high dimensional tables, where dimensionality of a cross-table refers to the number of variables. It allowed to transform nonmodel- based to model-based methods providing the equation of a mathematical model, the use of estimation method and variety of visualizing tools. This paper describes how complex qualitative data may be described by a mathematical model. One of the method presented is log-linear analysis.
EN
The main purpose of this article is to describe a dependence between prices of flats and index of creditworthiness in Poland. In the empirical part of this paper the author tests mentioned relations according to Engle-Granger's procedure. Moreover the long time relation had been verified by Johansen's procedure and a VAR model. This case leads to the examination and estimation cointegration with testing lags between very important variables on real estate market in Poland. The database used in the research contains monthly observations from the middle of 2010 to the beginning of 2014.
XX
Celem naszym było porównanie kryterium Akaike i metody Hellwiga oraz wykazanie, który z tych sposobów jest bardziej efektywnym narzędziem doboru zmiennych objaśniających do modelu i tym samym uzyskania modelu optymalnego. Aby umożliwić porównanie opracowano specjalny program w języku R (The R Project for Statistical Computing, R language). Program ten oparty jest na prostej symulacji, która polega na wygenerowaniu zestawu danych posiadających rozkład normalny, a następnie zbudowaniu modelu liniowego, w którym zmienna objaśniana jest zależna od danych wcześniej wygenerowanych. W kolejnym etapie zastosowane są analizowane metody wyboru modelu, czyli sposoby Akaike i Hellwiga, a następnie dokonywane jest porównanie, która z tych metod wskazała właściwy model. Przeprowadzenie symulacji według różnych parametrów pozwoliło porównać skuteczność omawianych metod doboru zmiennych objaśniających. Następnie przeprowadzono porównanie tychże metod na podstawie budowy modeli wykorzystujących dane empiryczne. Otrzymane wyniki stały się solidną podstawą porównania kryterium informacyjnego Akaike oraz metody Hellwiga. Pozwoliły one na wskazanie, który z tych sposobów jest właściwym narzędziem doboru zmiennych objaśniających do modelu ekonometrycznego. (fragment tekstu)
EN
This paper presents a comparison of the Akaike Information Criterion (AIC) and the Hellwig Method as methods that select explanatory variables to a model and thus enable a choice of the true model. This comparison was made in two ways. At first, the simulations were constructed in the R software (The R Project for Statistical Computing). The purpose of these simulations was to identify which of the analyzed methods more times indicates the true model. Secondly, a comparison of both methods was made on the basis of empirical data. From the set of potential explanatory variables, a set of variables was selected according to the Akaike method and the other set according to the Hellwig method. On the basis of each of the selected sets, a model was developed. Subsequently, both models were compared in terms of their adjusted coefficients of determination, standard errors of estimate and the goodness-of-fit. Results given by the simulations and results coming from the empirical models analysis indicated that the Akaike Information Criterion is a better, more efficient and more reliable tool for selecting the optimal set of explanatory variables and the true econometric model. (original abstract)
EN
Procedures and cause descriptive model, dynamic consistent model and vector autoregression model were used for modeling of selected variables characterizing the economy of the Upper Silesia. To assess the conformity of these three types of models the AIC, BIC, coefficient of determination and corrected coefficient of determination were used. Despite the use of different procedures, final results show similar quality of models.
EN
In this paper the authors present a nonparametric method of estimating the parameters of the linear econometric model, which is the method of least absolute deviations (LAD). The aim of this article is to examine the extent to which the parameter estimation method of least absolute deviations is resistant to changes in parameter values in case of outliers. In this paper, a hypothetical example examines the impact of the so-called outliers on the model parameters estimated by OLS methods and LAD respectively. In addition, the work raises the problem of the use of permutation methods MRPP in testing certain statistical hypotheses when the distributions of examined random variables distributions are not normal.
EN
In seventies, structural models were subjected to the criticism more and more. In the article the author presented reasons of the criticism of structural models and theoretical bases of vector autoregression models which was introduced in article C. A. Sims in 1980. An example of using VAR models was also expressed for the modelling of macroeconomic variables. In the summary the author described defects and virtues of VAR models in the context of the structural attempt at the econometric modelling.
PL
W badaniu wyselekcjonowane zostaną maksymalne stany wód dla wybranych horyzontów czasowych. W ten sposób otrzymane zostaną realizacje określonych zmiennych losowych, które aproksymowane będą odpowiednimi rozkładami Poissona. Z dopasowanych teoretycznych rozkładów Poissona policzone zostaną prawdopodobieństwa przekroczenia progów ostrzegawczego i alarmowego, które traktowane będą jako miary ryzyka zagrożenia powodziowego
EN
The main purpose of this article is the using the Poisson distribution to estimate the risk of flood danger on the Odra river in Oława. Lower Silesia belongs to one of the most dangerous regions in Poland of waterboarding and floods. In research the maximas of water level will be selected for chosen times horisont. In this way, given determined random variables, will be approximated by relevant Poisson distribution. In fitted theoretical Poisson distribution it will be counted the probability od transgression warning and alarm level which will be treated as a risk measure of flood danger.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.