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Wyszukujesz frazę "stratified sampling" wg kryterium: Temat


Wyświetlanie 1-12 z 12
Tytuł:
Variance estimation in stratified adaptive cluster sampling
Autorzy:
Yasmeen, Uzma
Noor-ul-Amin, Muhammad
Hanif, Muhammad
Powiązania:
https://bibliotekanauki.pl/articles/2034098.pdf
Data publikacji:
2022
Wydawca:
Główny Urząd Statystyczny
Tematy:
variance estimator
stratified sampling
stratified adaptive cluster sampling (SACS)
Opis:
In many sampling surveys, the use of auxiliary information at either the design or estimation stage, or at both these stages is usual practice. Auxiliary information is commonly used to obtain improved designs and to achieve a high level of precision in the estimation of population density. Adaptive cluster sampling (ACS) was proposed to observe rare units with the purpose of obtaining highly precise estimations of rare and specially clustered populations in terms of least variances of the estimators. This sampling design proved to be more precise than its more conventional counterparts, including simple random sampling (SRS), stratified sampling, etc. In this paper, a generalised estimator is anticipated for a finite population variance with the use of information of an auxiliary variable under stratified adaptive cluster sampling (SACS). The bias and mean square error expressions of the recommended estimators are derived up to the first degree of approximation. A simulation study showed that the proposed estimators have the least estimated mean square error under the SACS technique in comparison to variance estimators in stratified sampling.
Źródło:
Statistics in Transition new series; 2022, 23, 1; 173-184
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Developing calibration estimators for population mean using robust measures of dispersion under stratified random sampling
Autorzy:
Audu, Ahmed
Singh, Rajesh
Khare, Supriya
Powiązania:
https://bibliotekanauki.pl/articles/1054567.pdf
Data publikacji:
2021-06-04
Wydawca:
Główny Urząd Statystyczny
Tematy:
calibration
outliers
percentage relative efficiency (PRE)
stratified sampling
Opis:
In this paper, two modified, design-based calibration ratio-type estimators are presented. The suggested estimators were developed under stratified random sampling using information on an auxiliary variable in the form of robust statistical measures, including Gini’s mean difference, Downton’s method and probability weighted moments. The properties (biases and MSEs) of the proposed estimators are studied up to the terms of firstorder approximation by means of Taylor’s Series approximation. The theoretical results were supported by a simulation study conducted on four bivariate populations and generated using normal, chi-square, exponential and gamma populations. The results of the study indicate that the proposed calibration scheme is more precise than any of the others considered in this paper.
Źródło:
Statistics in Transition new series; 2021, 22, 2; 125-142
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sample allocation decisions for program evaluation: a case of multiplicative effect on units due to the developmental initiatives carried out in a phased manner
Autorzy:
Pandey, R.
Powiązania:
https://bibliotekanauki.pl/articles/38469.pdf
Data publikacji:
2010
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
developmental initiative
stratified sampling
temporal impact
sample allocation
weight
Źródło:
Folia Forestalia Polonica. Series A . Forestry; 2010, 52, 2
0071-6677
Pojawia się w:
Folia Forestalia Polonica. Series A . Forestry
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:
Zwiększenie efektywności inwentaryzacji lasu metodą losowania warstwowego
Improving effectiveness of forest inventory by stratified sampling
Autorzy:
Banaś, J.
Drozd, M.
Zięba, S.
Bujoczek, L.
Powiązania:
https://bibliotekanauki.pl/articles/986979.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
inwentaryzacja lasu
losowanie warstwowe
poprawa efektywnosci
sampling design
inventory precision
stratified sampling
Opis:
The purpose of the stratification is to group stands basing on the homogeneity of the measured feature. During periodic forest inventory in Poland, strata are created on the basis of age and the main species in stand within the boundary of forest district. In this work an improvement of distinguishing the strata during the forest inventory is presented. Three variants are considered: (1) distinguishing homogeneous strata in boundary of the whole forest district, not separately in forest subdistricts, (2) splitting species−aged strata into homogeneous substrata with respect to site quality, and (3) dividing strata of stands in the regeneration class with respect to stand density. Study was conducted in four mountain forest districts located in the Kłodzko Basin (SW Poland). Total area of these stands amounted to 43,052 ha, where 6,648 sample plots were established during the periodic inventory. ANOVA was used to test significance of the differences in tree volume and to assess variability reducing in distinguished substrata. Results indicated that in stands with age up to 70 years mean volume of trees on the sample plot does not differ significantly between sites, but in older stands difference was significant. Dividing age−species strata of stands older than 70 years into substrata according to site conditions influenced reduction of volume variability from 10 to 57% in newly created substrata. Dividing strata consisted of stands in regeneration class according to stand density index allowed to decrease the volume variability from 9 to 20%. Mean volume of trees in stands on similar sites does no differ significantly between subdistricts in the same forest district. Strata distinguished within the whole forest district are bigger and represented by more sample plots than on the subdistrict level, which significantly reduced standard error of volume and improved effectiveness of stratification in forest inventory.
Źródło:
Sylwan; 2017, 161, 10; 804-811
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of Population Mean in Post-Stratified Sampling Using Known Value of Some Population Parameter(S)
Autorzy:
Onyeka, Aloy C.
Powiązania:
https://bibliotekanauki.pl/articles/465814.pdf
Data publikacji:
2012
Wydawca:
Główny Urząd Statystyczny
Tematy:
Auxiliary information
general family of estimators post-stratified sampling
mean squared errors
Opis:
Following Khoshnevisan et.al. (2007) and Koyuncu and Kadilar (2009), this paper develops a general family of combined estimators of the population mean in post-stratified sampling (PSS) scheme, using known values of some population parameters of an auxiliary variable. Properties of the proposed family of estimators, including conditions for optimal efficiency, are obtained up to first order approximations. The results are illustrated empirically.
Źródło:
Statistics in Transition new series; 2012, 13, 1; 65-78
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Size Effects in Problems of Footings on Sand within Micro-Polar Hypoplasticity
Autorzy:
Tejchman, J.
Górski, J.
Powiązania:
https://bibliotekanauki.pl/articles/241079.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
footing
micro-polar hypoplasticity
sand
shear localization
size effect
stratified sampling
void ratio
Opis:
Numerical FE investigations of size effects in problems of footings on sand were performed. Micro-polar hypoplastic constitutive model was used to describe a mechanical behaviour of a cohesionless granular material during a monotonic deformation path. The FE analyses were carried out with three different footing widths. In deterministic calculations, a uniform distribution of initial void ratio was used. In statistical calculations, initial void ratios took the form of random spatial fields described by a truncated Gaussian random distribution. In order to reduce the number of stochastic realizations without sacrificing the accuracy of the calculations, a stratified sampling method was applied. The numerical results were compared with corresponding laboratory tests by Tatsuoka et al (1997). The numerical results show that the bearing capacity of footings decreases with increasing specimen size. If the initial void ratio is stochastically distributed, the mean bearing capacity of footings may be larger than the deterministic value. The statistical size effect is smaller than the deterministic one.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2008, 55, 3-4; 95-124
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Warstwowanie drzewostanów w statystycznej metodzie reprezentacyjnej pomiaru miąższości obrębu leśnego – praktyczna realizacja założeń
Problems with strata determination in application of statistical method of growing stock assessment at forest division level
Autorzy:
Jabłoński, M.
Powiązania:
https://bibliotekanauki.pl/articles/973245.pdf
Data publikacji:
2010
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lasy
inwentaryzacja
losowanie warstwowe
warstwy gatunkowo-wiekowe
dane inwentaryzacyjne
leśnictwo
obręby leśne
miąższość drzewostanów
stratified sampling
auxiliary data
Opis:
New method of forest inventory based on stratified sampling was implemented in the State Forests National Forest Holding in Poland in 2003. Updated stands characteristics from previous inventory are used as auxiliary information to determine sample size and strata system, while results of the inventory are presented according to the new stands description. Paper presents analysis and assessment of the differences between updated and new data as well as their influence on sample size requirement and number of strata.
Źródło:
Sylwan; 2010, 154, 06; 397-404
0039-7660
Pojawia się w:
Sylwan
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:
Improved Estimators for Simple Random Sampling and Stratified Random Sampling under Second Order of Approximation
Autorzy:
Sharma, Prayas
Powiązania:
https://bibliotekanauki.pl/articles/465938.pdf
Data publikacji:
2014
Wydawca:
Główny Urząd Statystyczny
Tematy:
simple random sampling
stratified random sampling population mean
study variable
exponential ratio type estimators
bias and MSE
Opis:
Singh and Solanki (2012) and Koyuncu (2012) proposed estimators for estimating population meanY. Up to the first order of approximation and under optimum conditions, the minimum mean squared error of both the estimators is equal to the MSE of the regression estimator. In this paper, we have tried to find out the second order biases and mean square errors of these estimators using information on auxiliary variable based on simple random sampling. Finally, we have compared the performance of these estimators with some numerical illustration.
Źródło:
Statistics in Transition new series; 2014, 15, 3; 379-390
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:
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
    Wyświetlanie 1-12 z 12

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