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  • Author: Ksenija Dumičić x
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Decision making based on single and double acceptance sampling plans for assessing quality of lots

Background: Acceptance sampling is a statistical tool of quality control. Sampling plans and operating characteristic (OC) curves are very useful for conducting acceptance sampling and provide the quality manager with tools to evaluate the quality of a production run or shipment. There are developed different sampling plans, but common used in practise are single and double acceptance sampling plans. Objectives: The goal of the paper is to test if applying of single and double sampling plan can lead to statistically significant different conclusion about quality level of observed lot. Methods/Approach: Statistical tests of difference in proportions are used to test if there is some statistically significant difference in probabilities of lot fraction defectives between a single and a double sampling plan at the same levels of probability of acceptance. Results: The results of the analysis show that in some cases there is statistically significant difference. Namely, the quality manager should be careful when he chooses to use, instead of the first, the second sampling plan with different parameters because on that way he could make statistically significant different conclusion about quality level of observed lot. Conclusions: The paper shows that some intentional manipulations by using different sampling plans are possible.

Abstract

Background: In recent years’ income inequality has been an economic issue. The primary instrument for redistributing income is personal income tax. However, based on economic theory income inequality concerns indicators such as wages, transfer payments, taxes, social security contributions, and geographical mobility. Objectives: The objective of this paper is to examine the impact of certain labor market indicators on personal income taxation in Federation of Bosnia and Herzegovina (FB&H). Methods/Approach: Since personal income taxation consists of a very broad definition and for the purpose of this research only, income from dependent (employment) activity is observed. The econometric analysis is conducted using error correction modeling, as well as forecast errors variance decomposition. Results: The error correction model is estimated, and the cointegrating equation indicates that monthly wage and number of employees statistically significantly positively affect personal income taxes in FB&H in the long-run. After two years, the selected labor market indicators explain a considerable part of forecasting error variance of personal income tax revenues. Conclusions: The implementation of reforms in the labor market and tax policies of the FB&H is suggested. In order to achieve necessary reforms, efficient governance and general stable political environment are required.

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Editorial for

The 11th International Symposium on Operational Research (SOR'11) was organized by Slovenian Society INFORMATIKA - Section for Operational Research (SDI-SOR) in Dolenjske Toplice, Slovenia, during the week of 28 - 30 September 2011. At SOR'11 it was decided to publish a Special Issue of Business Systems Research Journal (SI of BSRJ) on innovative approaches to OR methodology and its applications in business, micro and macro-economics, management, finance, social sciences, energy, environment, transport and other areas. The call for papers for SI of BSRJ was open, and it was directed to the participants of SOR'11 as well as to other researchers and practitioners from the field of OR. We have received 9 submissions for this special issue, some of them being extended journal versions of short conference papers from proceedings (Zadnik Stirn et al., 2011). Each submission was first reviewed by the Guest Editors, and the papers were then blind reviewed by two experts.

Abstract

Background: The stock exchange, as a regulated financial market, in modern economies reflects their economic development level. The stock market indicates the mood of investors in the development of a country and is an important ingredient for growth. Objectives: This paper aims to introduce an additional statistical tool used to support the decision-making process in stock trading, and it investigate the usage of statistical process control (SPC) methods into the stock trading process. Methods/Approach: The individual (I), exponentially weighted moving average (EWMA) and cumulative sum (CUSUM) control charts were used for gaining trade signals. The open and the average prices of CROBEX10 index stocks on the Zagreb Stock Exchange were used in the analysis. The statistical control charts capabilities for stock trading in the short-run were analysed. Results: The statistical control chart analysis pointed out too many signals to buy or sell stocks. Most of them are considered as false alarms. So, the statistical control charts showed to be not so much useful in stock trading or in a portfolio analysis. Conclusions: The presence of non-normality and autocorellation has great impact on statistical control charts performances. It is assumed that if these two problems are solved, the use of statistical control charts in a portfolio analysis could be greatly improved.

Abstract

Following Friedman’s permanent income hypothesis and Ando and Modigliani’s lifecycle hypothesis, this paper empirically studies the role of house prices and income in determining the dynamic behaviour of consumption in selected European post-transition economies using the panel vector autoregression (PVAR) approach and quarterly data covering the period from the first quarter of 2002 until the second quarter of 2012. With the shocks being recognized using the customary recursive identification scheme, we found that the response of personal consumption to the housing wealth shock is initially positive, but short lived.

Abstract

In this paper, based on the analysis of official FAOSTAT and EUROSTAT data on poultry meat for 38 European countries for years 2007 and 2009, two hypotheses were examined. Firstly, considering four clustering variables on poultry meat, i.e. production, export and import in kg/capita, as well as the producer price in US $/t, using descriptive exploratory and cluster analysis, the hypothesis that the clusters of countries may be recognized was confirmed. As a result six clusters of similar countries were distinguished. Secondly, based on multiple regression analysis, this paper proofs that there exists the statistically significant relationship of poultry meat production on export and import of that kind of meat, all measured in kg/capita. There is also a high correlation between production, as a dependent, and each of two independent variables.

Abstract

Background: By joining different regional economic trade agreements, countries achieve preferential trade liberalisation. There are four main types of regional economic agreements in the world today: free trade area, customs union, common market, and economic and monetary union.

Objectives: The goal of this paper is the measurement of the export market concentration for the largest European regional economic integrations in the period between 1995 and 2016.

Methods/Approach: Various concentration measures have been used in the measurement of export market concentration, but the emphasis is placed on the standardized Herfindahl-Hirschman index as the basic measure of trade concentration.

Results: Results of the analysis have shown that the highest concentration level of trade with countries worldwide is among the European Free Trade Association (EFTA) countries, whereas the EU-15 countries seem to have the lowest concentration level. On the other side, the Central European Free Trade Agreement (CEFTA) countries have the highest concentration level of trade with countries from the same group, and again the EU-15 countries have the lowest concentration level, which indicates that the CEFTA countries implemented deeper integration processes related to mutual intra-regional trade.

Conclusions: Deep integration processes led to lower values of export market concentration indices for intra-regional trade among countries of the same regional economic integration in comparison to trading with countries worldwide.

Abstract

Background: Hidden economy presents a major concern for all national economies, particularly for those of developing countries. Objectives: In this work, methods for determination of the size of hidden economy are discussed. Particular attention is devoted to the methods using electricity consumption as an indicator (the Lackó method and the Kaufmann and Kaliberda method). Methods/Approach: The modified Lackó method adapted for a single country and the sophisticated Kaufmann and Kaliberda method have been used. Results: It has been shown that such methods are effective in measurement of the hidden economy extent in small open economies exposed to severe external influences. The article presents results for Macedonia and their comparison with results for Croatia, as a good role-model for other states in Western Balkans. Conclusions: Model methods involving energy consumption are particularly efficient in determination of the size of the hidden economic sector in small open economies as those of the Western Balkan countries

Abstract

Personal income taxation remains an ongoing issue in Croatia. It is used as an important instrument of income redistribution. Moreover, it directly affects purchasing power of the working population. Numerous changes have been made in this type of taxation since the establishment of Croatian tax system. The aim of this paper is to analyse possible determinants of personal income taxation in Croatia. After offering brief insight into public finance theory regarding personal income taxation, the structure of personal income taxation in Croatia is explained. The empirical analysis of the determinants of personal income taxation in Croatia is conducted using cointegration analysis. Economic conditions, average monthly wage, and number of taxpayers are used as determinants of personal income tax used in this research. The cointegration analysis is conducted using monthly data from January 2008 to February 2016. The results of the research show a statistically significant negative impact of economic conditions and statistically significant positive impact of average monthly wage and number of taxpayers on personal income taxation in long run, what is in line with economic and public finance theory.

Abstract

The aim of this paper is to analyse the influence of the development level indicators on the e-commerce, i.e. on the online purchase by individuals, in selected European countries in 2013. In the analysis, the main variable under study and all the independent variables are included as standardised. Based on nine variables, the principal component analysis with varimax rotation was performed and the two extracted factors were used as the regressors in the multiple regression analysis. In the regression model both components, Factor 1, which includes seven variables, called Prosperity, Investing in Education and IT Infrastructure, and Awareness, and Factor 2, comprised of two variables, called IT Skills, are statistically significant at the significance level of 1%. Both factors show a positive correlation with the online purchase of individuals. Inclusion and analysis of distributions and impacts of even nine independent variables, which make up two distinct factors affecting the e-commerce, make a new contribution of this work.