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Wyświetlanie 1-15 z 27
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:
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:
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:
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:
Some linear regression type ratio exponential estimators for estimating the population mean based on quartile deviation and deciles
Autorzy:
Prasad, Shakti
Powiązania:
https://bibliotekanauki.pl/articles/1059039.pdf
Data publikacji:
2020-12-04
Wydawca:
Główny Urząd Statystyczny
Tematy:
Bias
Mean square error (MSE)
Auxiliary variable
Relative Efficiency (%)
Opis:
This paper deals some linear regression type ratio exponential estimators for estimating the population mean using the known values of quartile deviation and deciles of an auxiliary variable in survey sampling. The expressions of the bias and the mean square error of the suggested estimators have been derived. It was compared with the usual mean, usual ratio (Cochran (1977)), Kadilar and Cingi (2004, 2006) and Subzar et al. (2017) estimators. After comparison, the condition which makes the suggested estimators more efficient than others is found. To verify the theoretical results, numerical results are performed on two natural population data sets.
Źródło:
Statistics in Transition new series; 2020, 21, 5; 85-98
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Class of Regression Type Estimators in Survey Sampling
Autorzy:
Misra, Govind Charan
Yadav, Subhash Kumar
Shukla, Alok Kumar
Powiązania:
https://bibliotekanauki.pl/articles/465942.pdf
Data publikacji:
2011
Wydawca:
Główny Urząd Statystyczny
Tematy:
Auxiliary variable
Mean Squared Error
Ratio estimator
Regression type estimators
Opis:
A class of linear regression models has been proposed for the estimation of population mean and total when information regarding auxiliary variate is available in survey sampling using regression method of estimation by introducing a new auxiliary variable z, which may also be a function of the auxiliary variable x. The proposed model leads to reduction in mean squared error as compared to ordinary regression method of estimation. The improvement has been demonstrated over ordinary regression estimator and also on ratio estimator with the help of an empirical example.
Źródło:
Statistics in Transition new series; 2011, 12, 3; 579-586
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Better Estimator of Population Mean with Power Transformation Based on Ranked Set Sampling
Autorzy:
Mehta (Ranka), Nitu
Mandowara, V. L.
Powiązania:
https://bibliotekanauki.pl/articles/466002.pdf
Data publikacji:
2012
Wydawca:
Główny Urząd Statystyczny
Tematy:
ranked set sampling
ratio estimator
power transformation estimator auxiliary variable
Opis:
Ranked set sampling (RSS) was first suggested by McIntyre (1952) to increase the efficiency of estimate of the population mean. It has been shown that this method is highly beneficial to the estimation based on simple random sampling (SRS). There has been considerable development and many modifications were done on this method. This paper presents a modified ratio estimator using prior value of coefficient of kurtosis of an auxiliary variable x, with the intention to improve the efficiency of ratio estimator in ranked set sampling. The first order approximation to the bias and mean square error (MSE) of the proposed estimator are obtained. A generalized version of the suggested estimator by applying the Power transformation is also presented.
Źródło:
Statistics in Transition new series; 2012, 13, 3; 551-558
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:
Heteroscedastic Discriminant Analysis Combined with Feature Selection for Credit Scoring
Autorzy:
Stąpor, Katarzyna
Smolarczyk, Tomasz
Fabian, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/465652.pdf
Data publikacji:
2016
Wydawca:
Główny Urząd Statystyczny
Tematy:
heteroscedastic discriminant analysis
feature subset selection
variable importance
credit scoring model
Opis:
Credit granting is a fundamental question and one of the most complex tasks that every credit institution is faced with. Typically, credit scoring databases are often large and characterized by redundant and irrelevant features. An effective classification model will objectively help managers instead of intuitive experience. This study proposes an approach for building a credit scoring model based on the combination of heteroscedastic extension (Loog, Duin, 2002) of classical Fisher Linear Discriminant Analysis (Fisher, 1936, Krzyśko, 1990) and a feature selection algorithm that retains sufficient information for classification purpose. We have tested five feature subset selection algorithms: two filters and three wrappers. To evaluate the accuracy of the proposed credit scoring model and to compare it with the existing approaches we have used the German credit data set from the study (Chen, Li, 2010). The results of our study suggest that the proposed hybrid approach is an effective and promising method for building credit scoring models.
Źródło:
Statistics in Transition new series; 2016, 17, 2; 265-280
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:
Ratio estimation of two population means in two-phase stratified random sampling under a scrambled response situation
Autorzy:
Das, Pitambar
Singh, Garib Nath
Bandyopadhyay, Arnab
Powiązania:
https://bibliotekanauki.pl/articles/31342165.pdf
Data publikacji:
2023-12-07
Wydawca:
Główny Urząd Statystyczny
Tematy:
stratified random sampling
scrambled response
auxiliary variable
mean square error
simulation study
Opis:
In this paper, we have described the development of an effective two-phase stratified random sampling estimation procedure in a scrambled response situation. Two different exponential, regression-type estimators were formed separately for different structures of two-phase stratified sampling schemes. We have studied the properties of the suggested strategy. The performance of the proposed strategy has been demonstrated through numerical evidence based on a data set of a natural population and a population generated through simulation studies. Taking into consideration the encouraging findings, suitable recommendations for survey statisticians are prepared for the application of the proposed strategy in real-life conditions.
Źródło:
Statistics in Transition new series; 2023, 24, 5; 45-61
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Advances in estimation by the item sum technique in two move successive sampling
Autorzy:
Priyanka, Kumari
Trisandhya, Pidugu
Powiązania:
https://bibliotekanauki.pl/articles/19900669.pdf
Data publikacji:
2023-09-08
Wydawca:
Główny Urząd Statystyczny
Tematy:
Sensitive variable
Successive moves
Population mean
Variance
Mean squared error
Optimum matching fraction
Opis:
The present article proposes an estimator using the Item Sum Technique (IST) for the estimation of dynamic sensitive population mean using non-sensitive auxiliary information in the two-move successive sampling. Properties of the proposed IST estimator have been analysed. Possible allocation designs for allocating long-list and short-list samples pertaining to the IST have been elaborated. The comparison between various allocation designs has been carried out. Theoretical considerations have been integrated with numerical as well as simulation studies to show the working version of the proposed IST estimators in the two-move successive sampling.
Źródło:
Statistics in Transition new series; 2023, 24, 4; 123-138
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 27

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