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Your search keyword '"Szczepańska-Álvarez, Anna"' showing total 14 results
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14 results on '"Szczepańska-Álvarez, Anna"'

7. Application of the ρV coefficient and distance correlation to the analysis of multivariate association.

Author

Janiszewska, Malwina, Szczepańska-Álvarez, Anna, and Zawieja, Emilia

Subjects
*STATISTICAL correlation, *MULTIVARIATE analysis
Abstract

The aim of this paper is to study the association between two random vectors related to two groups of characteristics. To analyze the multivariate association, the ρV coefficient and distance correlation are used. Two methods (classical and recent) are compared and illustrated with real data. [ABSTRACT FROM AUTHOR]

Published
2021
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11. Uszkodzenia drzew w następstwie trzebieży wczesnych w nizinnych drzewostanach świerkowych

Author

Bembenek, Mariusz, Giefing, Dieter F., Karaszewski, Zbigniew, Mederski, Piotr S., and Szczepańska-Álvarez, Anna

Subjects
tree damage, early thinning, timber harvest methods, spruce
Abstract

The paper presents analysis of tree damage after early thinning in lowland spruce stands. Percentage of tree with damage and weighted damage index (WDI) were considered. Three different thinning operations were analysed, in which different cutting method was applied. The smallest level of damage was observed when short wood system (SWS) was used. There were no significant differences between frequency of damage when full tree (FTS) and long wood (LWS) systems were compared., Sylwan 157 (10): 747-753

Published
2013
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12. Uszkodzenia drzew w nizinnych drzewostanach świerkowych podczas zabiegu trzebieży późnej

Author

Bembenek, Mariusz, Giefing, Dieter F., Karaszewski, Zbigniew, Mederski, Piotr S., and Szczepańska-Álvarez, Anna

Subjects
tree damage, Norway spruce, thinning operations
Abstract

The paper studies tree damage after late thinning operation in lowland spruce stands. The research was done in the 4ͭʰ age class stands, where three different methods of timber harvesting were applied: full tree system (FTS), long wood system (LWS), short wood system (SWS). The lowest level of damage was observed in SWS., Sylwan 157 (12): 892-898

Published
2013
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13. Estimation equations for multivariate linear models with Kronecker structured covariance matrices.

Author

Szczepańska-Álvarez, Anna, Hao, Chengcheng, Liang, Yuli, and Rosen, Dietrich von

Subjects
*COVARIANCE matrices, *ESTIMATION theory, *MULTIVARIATE analysis, *LINEAR statistical models, *MAXIMUM likelihood statistics
Abstract

The aim of the paper is to determine maximum-likelihood estimation equations. Observations follow a multivariate normal distribution,, where,anddescribe the unknown covariance structure between rows and columns of, respectively. Imposing restrictions onandfour types of covariance structures will be considered. [ABSTRACT FROM AUTHOR]

Published
2017
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14. A simulation study of the Bennett test and Miller test for coefficients of variation.

Author

Zawieja, Bogna and Szczepańska-Álvarez, Anna

Subjects
*VARIATIONAL approach (Mathematics), *SAMPLE size (Statistics), *DATA analysis, *EMPIRICAL research, *SIMULATION methods & models
Abstract

In the article, properties of the Bennett test and Miller test are analyzed. Assuming that the sample size is the same for each sample and considering the null hypothesis that the coefficients of variation forkpopulations are equal against the hypothesis thatk− 1 coefficients of variation are the same but differ from the coefficient of variation for thekth population, the empirical significance level and the power of the test are studied. Moreover, the dependence of the test statistic and the power of the test on the ratio of coefficients of variation are considered. The analyses are performed on simulated data. [ABSTRACT FROM AUTHOR]

Published
2017
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