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Tytuł:
Variable selection in multivariate functional data classification
Autorzy:
Górecki, Tomasz
Krzyśko, Mirosław
Wołyński, Waldemar
Powiązania:
https://bibliotekanauki.pl/articles/1194458.pdf
Data publikacji:
2019-07-02
Wydawca:
Główny Urząd Statystyczny
Tematy:
multivariate functional data
variable selection
dCov
HSIC
classification
Opis:
A new variable selection method is considered in the setting of classification with multivariate functional data (Ramsay and Silverman (2005)). The variable selection is a dimensionality reduction method which leads to replace the whole vector process, with a low-dimensional vector still giving a comparable classification error. Various classifiers appropriate for functional data are used. The proposed variable selection method is based on functional distance covariance (dCov) given by Székely and Rizzo (2009, 2012) and the Hilbert-Schmidt Independent Criterion (HSIC) given by Gretton et al. (2005). This method is a modification of the procedure given by Kong et al. (2015). The proposed methodology is illustrated with a real data example.
Źródło:
Statistics in Transition new series; 2019, 20, 2; 123-138
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Order Statistics of Auxiliary Variable to Estimation the Population Mean
Autorzy:
Wywiał, Janusz L.
Powiązania:
https://bibliotekanauki.pl/articles/465810.pdf
Data publikacji:
2012
Wydawca:
Główny Urząd Statystyczny
Tematy:
Order statistic
sample quantile
auxiliary variable
sampling scheme
sampling design
concomitant
Opis:
Estimation of the population average in a finite population by means of sampling strategies dependent on an auxiliary variable highly correlated with a variable under study is considered. The sample is drawn with replacement on the basis of the probability distribution of an order statistic of the auxiliary variable. Observations of the variable under study are the values of the concomitant of the order statistic. The mean of the concomitant values is the estimator of a population mean of the variable under study. The expected value and the variance of the estimator are derived. The limit distributions of the considered estimators were considered. Finally, on the basis of simulation analysis, the accuracy of the estimator is considered.
Źródło:
Statistics in Transition new series; 2012, 13, 2; 279-286
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimating population coefficient of variation using a single auxiliary variable in simple random sampling
Autorzy:
Singh, Rajesh
Mishra, Madhulika
Powiązania:
https://bibliotekanauki.pl/articles/1186918.pdf
Data publikacji:
2019-12-10
Wydawca:
Główny Urząd Statystyczny
Tematy:
coefficient of variation
simple random sampling
auxiliary variable
mean square error
Opis:
This paper proposes an improved estimation method for the population coefficient of variation, which uses information on a single auxiliary variable. The authors derived the expressions for the mean squared error of the proposed estimators up to the first order of approximation. It was demonstrated that the estimators proposed by the authors are more efficient than the existing ones. The results of the study were validated by both empirical and simulation studies.
Źródło:
Statistics in Transition new series; 2019, 20, 4; 89-111
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ratio-To-Regression Estimator In Successive Sampling Using One Auxiliary Variable
Autorzy:
Ralte, Zoramthanga
Das, Gitasree
Powiązania:
https://bibliotekanauki.pl/articles/973550.pdf
Data publikacji:
2015
Wydawca:
Główny Urząd Statystyczny
Tematy:
ratio-to-regression estimator
auxiliary variable
successive sampling
bias
mean square error
optimum replacement policy
Opis:
The problem of estimation of finite population mean on the current occasion based on the samples selected over two occasions has been considered. In this paper, first a chain ratio-to-regression estimator was proposed to estimate the population mean on the current occasion in two-occasion successive (rotation) sampling using only the matched part and one auxiliary variable, which is available in both the occasions. The bias and mean square error of the proposed estimator is obtained. We proposed another estimator, which is a linear combination of the means of the matched and unmatched portion of the sample on the second occasion. The bias and mean square error of this combined estimator is also obtained. The optimum mean square error of this combined estimator was compared with (i) the optimum mean square error of the estimator proposed by Singh (2005) (ii) mean per unit estimator and (iii) combined estimator suggested by Cochran (1977) when no auxiliary information is used on any occasion. Comparisons are made both analytically as well as empirically by using real life data.
Źródło:
Statistics in Transition new series; 2015, 16, 2; 183-202
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sampling Designs Proportionate to Sum of Two Order Statistics of Auxiliary Variable
Autorzy:
Wywiał, Janusz L.
Powiązania:
https://bibliotekanauki.pl/articles/465790.pdf
Data publikacji:
2013
Wydawca:
Główny Urząd Statystyczny
Tematy:
sampling design
order statistic
sample quantile
auxiliary variable
Horvitz-Thompson statistic
inclusion probabilities
sampling scheme
ratio estimator
Opis:
In this paper the case of a conditional sampling design proportional to the sum of two order statistics is considered. Several strategies including the Horvitz-Thompson estimator and ratio-type estimators are discussed. The accuracy of these estimators is analyzed on the basis of computer simulation experiments.
Źródło:
Statistics in Transition new series; 2013, 14, 2; 231-248
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of binary data transformation in categorical data clustering
Autorzy:
Cibulková, Jana
Šulc, Zdenek
Sirota, Sergej
Rezanková, Hana
Powiązania:
https://bibliotekanauki.pl/articles/1194463.pdf
Data publikacji:
2019-07-02
Wydawca:
Główny Urząd Statystyczny
Tematy:
hierarchical cluster analysis
nominal variable
binary variable
categorical data
similarity measures
evaluation criteria
generated data
Opis:
This paper focuses on hierarchical clustering of categorical data and compares two approaches which can be used for this task. The first one, an extremely common approach, is to perform a binary transformation of the categorical variables into sets of dummy variables and then use the similarity measures suited for binary data. These similarity measures are well examined, and they occur in both commercial and non-commercial software. However, a binary transformation can possibly cause a loss of information in the data or decrease the speed of the computations. The second approach uses similarity measures developed for the categorical data. But these measures are not so well examined as the binary ones and they are not implemented in commercial software. The comparison of these two approaches is performed on generated data sets with categorical variables and the evaluation is done using both the internal and the external evaluation criteria. The purpose of this paper is to show that the binary transformation is not necessary in the process of clustering categorical data since the second approach leads to at least comparably good clustering results as the first approach.
Źródło:
Statistics in Transition new series; 2019, 20, 2; 33-47
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of finite population mean using two auxiliary variables under stratified random sampling
Autorzy:
Yadav, Rohini
Tailor, Rajesh
Powiązania:
https://bibliotekanauki.pl/articles/1358426.pdf
Data publikacji:
2020-03-23
Wydawca:
Główny Urząd Statystyczny
Tematy:
Study variable
auxiliary variable
stratified random sampling
dual to ratio estimator
bias and mean squared error
Opis:
This paper addresses the problem of an alternative approach to estimating the population mean of the study variable with the help of the auxiliary variable under stratified random sampling. The properties of the suggested estimator have been studied under large sample approximation. It has been demonstrated that the suggested estimator is more efficient than other considered estimators. To judge the merits of the proposed estimator, an empirical study has been carried out to support the present study.
Źródło:
Statistics in Transition new series; 2020, 21, 1; 1-12
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Almost Unbiased Ratio and Product Type Exponential Estimators
Autorzy:
Yadav, Rohini
Upadhyaya, Lakshmi N.
Singh, Housila P.
Chatterjee, S.
Powiązania:
https://bibliotekanauki.pl/articles/465956.pdf
Data publikacji:
2012
Wydawca:
Główny Urząd Statystyczny
Tematy:
study variable
auxiliary variable
almost unbiased ratio-type and product-type exponential estimators bias
mean squared error
Opis:
This paper considers the problem of estimating the population mean Y of the study variate y using information on auxiliary variate x. We have suggested a generalized version of Bahl and Tuteja (1991) estimator and its properties are studied. It is found that asymptotic optimum estimator (AOE) in the proposed generalized version of Bahl and Tuteja (1991) estimator is biased. In some applications, biasedness of an estimator is disadvantageous. So applying the procedure of Singh and Singh (1993) we derived an almost unbiased version of AOE. A numerical illustration is given in the support of the present study.
Źródło:
Statistics in Transition new series; 2012, 13, 3; 537-550
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improved Separate Ratio Exponential Estimator for Population Mean Using Auxiliary Information
Autorzy:
Yadav, Rochini
Upadhyaya, Lakshmi N.
Singh, Housila P.
Chatterjee, S.
Powiązania:
https://bibliotekanauki.pl/articles/465985.pdf
Data publikacji:
2011
Wydawca:
Główny Urząd Statystyczny
Tematy:
Study variable
auxiliary variable
stratified random sampling
separate ratio estimator
separate product estimator
bias and mean squared error
Opis:
This paper advocates the improved separate ratio exponential estimator for population mean of the study variable y using the information based on auxiliary variable x in stratified random sampling. The bias and mean squared error (MSE) of the suggested estimator have been obtained upto the first degree of approximation. The theoretical and numerical comparisons are carried out to show the efficiency of the suggested estimator over sample mean estimator, usual separate ratio and separate product estimator.
Źródło:
Statistics in Transition new series; 2011, 12, 2; 401-412
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of Selected Approaches to Clustering Categorical Variables
Autorzy:
Šulc, Zdeněk
Powiązania:
https://bibliotekanauki.pl/articles/465958.pdf
Data publikacji:
2014
Wydawca:
Główny Urząd Statystyczny
Tematy:
variable clustering
nominal variables
association measures
similarity measures.
Opis:
This paper focuses on recently proposed similarity measures and their performance in categorical variable clustering. It compares clustering results using three recently developed similarity measures (IOF, OF and Lin measures) with results obtained using two association measures for nominal variables (Cramér’s V and the uncertainty coefficient) and with the simple matching coefficient (the overlap measure). To eliminate the influence of a particular linkage method on the structure of final clusters, three linkage methods are examined (complete, single, average). The created groups (clusters) of variables can be considered as the basis for dimensionality reduction, e.g. by choosing one of the variables from a given group as a representative for the whole group. The quality of resulting clusters is evaluated by the within-cluster variability, expressed by the WCM coefficient, and by dendrogram analysis. The examined similarity measures are compared and evaluated using two real data sets from a social survey.
Źródło:
Statistics in Transition new series; 2014, 15, 4; 591-610
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A calibrated synthetic estimator for small area estimation
Autorzy:
Iseh, Matthew Joshua
Enang, Ekaette Inyang
Powiązania:
https://bibliotekanauki.pl/articles/1827531.pdf
Data publikacji:
2021-09-06
Wydawca:
Główny Urząd Statystyczny
Tematy:
auxiliary variable
calibration estimation
simulation
synthetic estimation
Opis:
Synthetic estimators are known to produce estimates of population mean in areas where no sampled data are available, but such estimates are usually highly biased with invalid confidence statements. This paper presents a calibrated synthetic estimator of the population mean which addresses these problematic issues. Two known special cases of this estimator were obtained in the form of combined ratio and combined regression synthetic estimators, using selected tuning parameters under stratified sampling. In result, their biases and variance estimators were derived. The empirical demonstration of the usage involving the proposed calibrated estimators shows that they provide better estimates of the population mean than the existing estimators discussed in this study. In particular, the estimators were examined through simulation under three distributional assumptions, namely the normal, gamma and exponential distributions. The results show that they provide estimates of the mean displaying less relative bias and greater efficiency. Moreover, they prove more consistent than the existing classical synthetic estimator. The further evaluation carried out using the coefficient of variation provides additional confirmation of the calibrated estimator's advantage over the existing ones in relation to small area estimation.
Źródło:
Statistics in Transition new series; 2021, 22, 3; 15-30
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Conditional Simple Random Sample
Autorzy:
Wywiał, Janusz L.
Powiązania:
https://bibliotekanauki.pl/articles/465622.pdf
Data publikacji:
2014
Wydawca:
Główny Urząd Statystyczny
Tematy:
simple random sample
conditional sampling design
sampling scheme
inclusion probabilities
auxiliary variable
order statistics
Opis:
Estimation of the population average in a finite and fixed population on the basis of the conditional simple random sampling design dependent on order statistics of the auxiliary variable is studied. The sampling scheme implementing the sampling design is proposed. The inclusion probabilities are derived. The well known Horvitz-Thompson statistic under the conditional simple random sampling designs is considered as the estimator of population mean. Moreover, it was shown that the Horvitz-Thompson estimator under some particular cases of the conditional simple random sampling design is more accurate than the ordinary mean from the simple random sample.
Źródło:
Statistics in Transition new series; 2014, 15, 4; 525-534
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Horvitz-Thompson estimator based on theauxiliary variable
Autorzy:
Al-Jararha, J.
Sulaiman, Mazen
Powiązania:
https://bibliotekanauki.pl/articles/1358405.pdf
Data publikacji:
2020-03-23
Wydawca:
Główny Urząd Statystyczny
Tematy:
Horvitz-Thompson Estimator
Stratified Sampling Designs
Dual Calibration
GREG Type Estimator
Opis:
In this paper, the Horvitz and Thompson (1952) estimator will be modified; so that, the modified estimators will use the availability of the auxiliary variable. Furthermore, the modified estimators are extended to be used in stratified sampling designs. Empirical studies are given for comparison purposes.
Źródło:
Statistics in Transition new series; 2020, 21, 1; 37-54
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of Finite Population Mean Using Deciles of an Auxiliary Variable
Autorzy:
Subramani, J.
Kumarapandiyan, G.
Powiązania:
https://bibliotekanauki.pl/articles/466087.pdf
Data publikacji:
2013
Wydawca:
Główny Urząd Statystyczny
Tematy:
mean squared error
natural populations
simple random sampling
Opis:
The present paper deals with a class of modified ratio estimators for estimation of population mean of the study variable when the population deciles of the auxiliary variable are known. The biases and the mean squared errors of the proposed estimators are derived and compared with that of existing modified ratio estimators for certain known populations. Further, we have also derived the conditions for which the proposed estimators perform better than the existing modified ratio estimators. From the numerical study it is also observed that the proposed modified ratio estimators perform better than the existing modified ratio estimators.
Źródło:
Statistics in Transition new series; 2013, 14, 1; 75-88
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Method of Variable Selection for Binary Data Cluster Analysis
Autorzy:
Korzeniewski, Jerzy
Powiązania:
https://bibliotekanauki.pl/articles/466036.pdf
Data publikacji:
2016
Wydawca:
Główny Urząd Statystyczny
Tematy:
cluster analysis
market segmentation
selection of variables
binary data
k-means grouping
Opis:
Cluster analysis of binary data is a relatively poorly developed task in comparison with cluster analysis for data measured on stronger scales. For example, at the stage of variable selection one can use many methods arranged for arbitrary measurement scales but the results are usually of poor quality. In practice, the only methods dedicated for variable selection for binary data are the ones proposed by Brusco (2004), Dash et al. (2000) and Talavera (2000). In this paper the efficiency of these methods will be discussed with reference to the marketing type data of Dimitriadou et al. (2002). Moreover, the primary objective is a new proposal of variable selection method based on connecting the filtering of the input set of all variables with grouping of sets of variables similar with respect to similar groupings of objects. The new method is an attempt to link good features of two entirely different approaches to variable selection in cluster analysis, i.e. filtering methods and wrapper methods. The new method of variable selection returns best results when the classical k-means method of objects grouping is slightly modified.
Źródło:
Statistics in Transition new series; 2016, 17, 2; 295-304
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł

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