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Tests for Identifying the Unchanging Reference Component of Compositional Data using the Properties of the Coefficient of Variaiton

In analyses of compositional data, it is important to select a suitable unchanging component as a reference to detect the behavior of a single variable in isolation. This paper introduces two tests for detecting the unchanging component, based on a new approach that utilizes the coefficient of variation of component ratios. That is, the coefficient of variation of a compositional ratio is subject to change when the unchanging component is switched between the denominator and numerator, and the coefficient of variation tends to be small when the unchanging component occurs as the denominator against any arbitrary components (Test 1). In addition, the ratio of the component pair that gives the lowest coefficient of variation is most likely to represent the two unchanging components (Test 2). However, Tests 1 and 2 are not necessary and sufficient conditions for uniquely finding the unchanging component. To verify the effectiveness of the tests, 500 artificial data sets were analyzed and the results suggest that the tests are able to identify the unchanging component, although Test 1 underperforms when the data set includes a component with skewness greater than 0.5, and Test 2 fails when the data set includes components with a correlation coefficient greater than 0.75. These defects can be overcome by interpreting the two test results in a complementary manner. The proposed tests provide powerful yet simple criteria for identifying the unchanging component in compositional data; however, the reliability of this approach needs to be assessed in further studies

Universitat de Girona. Departament d’Informàtica i Matemàtica Aplicada

Altres contribucions: Universitat de Girona. Departament d’Informàtica i Matemàtica Aplicada
Autor: Ohta, T.
Arai, H.
Noda, A.
Data: 11 maig 2011
Resum: In analyses of compositional data, it is important to select a suitable unchanging component as a reference to detect the behavior of a single variable in isolation. This paper introduces two tests for detecting the unchanging component, based on a new approach that utilizes the coefficient of variation of component ratios. That is, the coefficient of variation of a compositional ratio is subject to change when the unchanging component is switched between the denominator and numerator, and the coefficient of variation tends to be small when the unchanging component occurs as the denominator against any arbitrary components (Test 1). In addition, the ratio of the component pair that gives the lowest coefficient of variation is most likely to represent the two unchanging components (Test 2). However, Tests 1 and 2 are not necessary and sufficient conditions for uniquely finding the unchanging component. To verify the effectiveness of the tests, 500 artificial data sets were analyzed and the results suggest that the tests are able to identify the unchanging component, although Test 1 underperforms when the data set includes a component with skewness greater than 0.5, and Test 2 fails when the data set includes components with a correlation coefficient greater than 0.75. These defects can be overcome by interpreting the two test results in a complementary manner. The proposed tests provide powerful yet simple criteria for identifying the unchanging component in compositional data; however, the reliability of this approach needs to be assessed in further studies
Format: application/pdf
Accés al document: http://hdl.handle.net/10256/13620
Llenguatge: eng
Editor: Universitat de Girona. Departament d’Informàtica i Matemàtica Aplicada
Col·lecció: CoDaWork 2011. The 4th International Workshop on Compositional Data Analysis
Drets: Tots els drets reservats
Matèria: Estadística matemàtica -- Congressos
Mathematical statistics -- Congresses
Variables (Matemàtica) -- Congressos
Variables (Mathematics) -- Congresses
Títol: Tests for Identifying the Unchanging Reference Component of Compositional Data using the Properties of the Coefficient of Variaiton
Tipus: info:eu-repo/semantics/conferenceObject
Repositori: DUGiDocs

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