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The impact of EU enlargement on the agricultural output and income in the member states

100%
Kobus P.
Problemy Rolnictwa Światowego
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2008
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vol. 03(18)
EN
The paper presents an analysis of the impact of the EU enlargement in 2004 on the agricultural output and incomes of the EU Member States. The main aim of the study is to test the significance of difference of reaction to enlargement in three distinct groups of members, namely the ‘old’ fifteen Member States, the ‘new’ ten Member States which accessed the EU on May 1st 2004, and the two ‘newest’ Member States, i.e. Romania and Bulgaria which accessed the EU on January 1st 2007. For the purpose of description of different countries behaviour a linear mixed model was applied.
2
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Modelling joint distribution of crop plant yields and prices with use of a copula function

100%
Kobus P.
Problemy Rolnictwa Światowego
|
2013
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vol. 13[28]
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issue 4
EN
The paper constitutes an attempt at modelling the joint distribution of crop plant yields and prices in Poland. The main objective of the paper was to examine the usefulness of the copula function for the task and the selection of suitable marginal distributions. The fit of a joint distribution based copula function was compared with multivariate normal distribution. It was revealed that the multivariate normal distribution is outperformed by a Gaussian copula with the following marginal distribution: yields of both crop plants – normal distribution, price of wheat – Burr distribution (type XII) and price of rapeseeds – lognormal distribution. The main advantages of the copula function were: the possibility to use different marginal distributions and ability to model non-elliptical twodimensional distributions. The practical implications of choosing the right joint distribution is demonstrated by comparing empirical quantiles of income for a given crop structure with theoretical quantiles based on the proposed joint distributions.
3
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Wheat yields variability in Poland at NUTS 2 level in context of production risk

100%
Kobus P.
Problemy Rolnictwa Światowego
|
2009
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vol. 06(21)
EN
The paper presents an analysis of the wheat yields variability in voivodeships of Poland. The main aim of the study is to present several possible indicators for the crop variability in the context of production risk. It is found that ignoring the long-term yield trends leads to a serious overestimation of production risk.
4
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Modelling wheat yields variability in Polish voivodships

100%
Kobus P.
Problemy Rolnictwa Światowego
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2010
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vol. 10(25)
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issue 3
EN
The paper presents an analysis of wheat yields variability in the voivodeships of Poland. The main aim of the study was to find out what are the statistical relationships between the wheat yield variability and the following factors: arable area, size of wheat production area, share of arable land used for wheat production, land quality and average yield. For that purpose a multiple linear regression was applied. It was found out that the detected spatial autocorrelation of wheat yields variability measured by standard deviations can be explained in 75% by the fitted model. Two of the considered variables showed a significant negative effect on this variability: the logarithm of arable area and the land quality, while the other two: the average wheat yield and the wheat production area displayed a significant positive effect on the variability. The effect of share of arable land used for wheat production itself was not significant.
5
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Wielowymiarowe metody statystyczne w analizie wyników ekonomiczno-produkcyjnych gospodarstw rolnych wybranych państw Unii Europejskiej

63%
Pietrzykowski R., Kobus P.
Problemy Rolnictwa Światowego
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2008
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vol. 04(19)
EN
Multivariate methods for analysis of the production and economic results in agricultural holdings in the EU countries are presented. Three methods were used: principal components analysis, cluster analysis and k-means method. The data base concerned 25 countries in the period of 1989- 2006.
PL
W pracy zaprezentowano wykorzystanie wielowymiarowych metod statystycznych do analizy wyników ekonomiczno-produkcyjnych gospodarstw rolnych w wybranych państwach Unii Europejskiej. Wykorzystano trzy metody statystyczne: analizę składowych głównych, analizę k-średnich oraz analizę skupień. Dane dotyczyły 25 państw EU w latach 1989-2006.
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