Auflistung nach Autor:in "Todorov, Valentin"

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Compositional tables analysis in coordinates
(Wiley, 2016) Facevicova, Kamila; Hron, Karel; Todorov, Valentin; Templ, Matthias
Compositional tables – a continuous counterpart to the contingency tables – carry relative information about relationships between row and column factors; thus, for their analysis, only ratios between cells of a table are informative. Consequently, the standard Euclidean geome- try should be replaced by the Aitchison geometry on the simplex that enables decomposition of the table into its independent and interactive parts. The aim of the paper is to find interpretable coordi- nate representation for independent and interaction tables (in sense of balances and odds ratios of cells, respectively), where further statistical processing of compositional tables can be performed. Theoretical results are applied to real-world problems from a health survey and in macroeconomics.
01A - Beitrag in wissenschaftlicher Zeitschrift
General approach to coordinate representation of compositional tables
(Wiley, 2018) Facevicova, Kamila; Hron, Karel; Todorov, Valentin; Templ, Matthias
Compositional tables can be considered a continuous counterpart to the well-known contingency tables. Their cells, which generally contain positive real numbers rather than just counts, carry relative information about relationships between two factors. Hence, compositional tables can be seen as a generalization of (vector) compositional data. Due to their relative character, compositions are commonly expressed in orthonormal coordinates using a sequential binary partition prior to being further processed by standard statistical tools. Unfortunately, the resulting coordinates do not respect the two-dimensional nature of compositional tables. Information about relationship between factors is thus not well captured. The aim of this paper is to present a general system of orthonormal coordinates with respect to the Aitchison geometry, which allows for an analysis of the interactions between factors in a compositional table. This is achieved using logarithms of odds ratios, which are also widely used in the context of contingency tables.
01A - Beitrag in wissenschaftlicher Zeitschrift
The software environment R for official statistics and survey methodology
(Austrian Statistical Society, 2016) Templ, Matthias; Todorov, Valentin
The open-source programming language and software environment R is currently one of the most widely used and popular software tools for statistics and data analysis. This contribution provides an overview of important R packages used in official statistics and survey methodology and discusses the usefulness of R in the daily work of a statistical office. Examples of activities and developments in R related projects in several national and international statistical offices are given. The focus is not only on the internal infrastructure that national and international statistical offices provide for using R but also on some interesting R related projects carried out in those institutes. Two particular packages (laeken and sdcMicro) and one data set (Statistics on Earnings Survey) are used to illustrate the usefulness (and the user-friendliness) of R and to present methods available in R. In addition, the access to international statistical databases like WDI of World Bank and UN COMTRADE with R is illustrated.
01A - Beitrag in wissenschaftlicher Zeitschrift