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Quantile Regression
Procházka, Jiří ; Bašta, Milan (advisor) ; Malá, Ivana (referee)
The thesis deals with brief introduction of the quantile regression theory. The thesis is divided into three thematic parts. In the first part the thesis deals with general introduction to the quantile regression, with theoretical aspects regarding quantile regression and with basic approaches to estimation of quantile regression parameters. The second part of the thesis focuses on general and asymptotic properties of the quantile regression. Goal of this part is to compare the quantile regression with traditional OLS regression and outline its possible application. In the third part the thesis describes statistical inference, construction of the confidence intervals and testing statistical hypotheses about quantile regression parameters. The goal of this part is to introduce traditional approach and the approach based on resampling procedures and in the end of the day perform mutual comparison of different approaches eventually propose partial modification.
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Impact of online user reviews on demand for PC and video games
Veselá, Anna ; Mičúch, Marek (advisor) ; Hurník, Jaromír (referee)
The thesis examines impact of online user reviews, expressed in 5-star rating system, on demand for PC and video games. Used weekly data are collected from www.amazon.co.uk for period 2000 - 2012. The thesis contributes to discussion which takes place between supporters of superstar theory and supporters of long tail theory. Panel structure of the dataset referred to application of fixed effects model for estimation of basic and extended model. Both estimates proved negative influence of assigned number of stars on sales rank. Basic model estimated influence of one unit change of stars on rank by 9 positions, extended model estimated this change to be 10 positions. Quantile estimate also proved negative influence of stars on sales rank. The influence is strongest for the lowest quantile of dependent variable (tau = 0,05) representing 5 % best-selling titles, where one unit change of stars causes change of 35 positions in opposite direction. With increasing quantiles this influence decreases to zero. It proves that within the market for PC and video games online user reviews contribute to superstar effect.
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Wage Inequality and Returns to Education: Evidence from Visegrad Countries
Votava, Tomáš ; Klosová, Anna (advisor) ; Pugh, Geoff (referee)
Wage inequality is a well-established phenomenon of contemporary labour markets both in the United States and Europe, frequently discussed in the contemporary labour economics literature. In the following paper, based on harmonised data of the EU-SILC database, a semi parametric technique of quantile regression has been applied together with the traditional OLS method in order to estimate the impact of returns to education on wages in the Visegrad Group countries, namely the Czech Republic, Poland, Hungary and Slovakia. The main aim of the analysis is to examine the returns to education in these countries in order to observe differences appearing across them as well as within selected groups formed according to both the highest level of education attained and a number of years spent in a paid work (experience).
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Econometric Analysis of Microeconomic Processes. Application on Wages in the Czech Republic
Kalčevová, Jana ; Pánková, Václava (advisor) ; Arlt, Josef (referee) ; Cahlík, Tomáš (referee)
This thesis is focused on wages models on the czech labor market in 1996 and 2002. Wages models are built on non-trivial mathematical background and parameters of given models are estimated by methods based on sum of squared residuals and also not often used quantile regression. The quantile regression theory is described in the thesis together with test statistics. Properties of estimations, demonstration examples and proposal of practical application are also indroduced. The theory was applied to two large-size data-files, recieved results show the difference between years 1996 and 2002; a comparison with European Union countries is also given.
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