• Proceedings of the Korean Statistical Society Conference
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• 2003.10a
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• pp.59-62
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• 2003

양곡소비량조사는 가구부문과 사업체부문에서 소비하는 주요식품의 소비량을 조사함과 동시에 주곡인 쌀의 재고량을 조사한다. 이 조사는 해마다 통계청에서 표본설계하여 실시하는 표본조사에 의존한다. 특히, 사업체 부문의 양곡소비량 조사는 응용절사법(Modified Cut-Off Sampling Method)에 의해 표본추출되어 매년 11월에 조사가 실시되고 있다. 2003년도 사업체 양곡소비량 및 재고량조사는 2001년 사업체기초통계조사와 광공업통계조사를 모집단으로 하여 22,320 대상업체 중에서 819업체를 전수조사하고 2,145 업체를 표본조사하여 전체를 추계한다.

• Survey Research
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• v.2 no.1
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• pp.73-86
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• 2001

In this paper. we conducted an empirical study to investigate the design and weighting effects on descriptive and analytic statistics. We compared the regression models using the design-based approach and the generalized estimating equations (GEEs) approach with the model-based approach through the design and weighting effects analysis.

• Survey Research
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• v.5 no.2
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• pp.31-48
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• 2004

We collected and analyzed 18 social surveys to assess the quality of samples with respect to region, gender, age-band, education level and occupation. We found in our samples that highly educated people and house wives are over-represented whereas low educated people, self-employed/blue collars and white collars are under-represented. To correct such sample distortions, we applied the iterative proportional weighting or the raking to our samples. We observed sizable changes in survey results. Also, the effective sample sizes were shrunken up to 20%-40%, that could be interpreted as the necessity of larger samples to meet the claimed sampling error limits.

• The Korean Journal of Applied Statistics
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• v.21 no.4
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• pp.675-694
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• 2008

We propose a new sampling design for the Korean Livestock Production Cost Survey. In this sampling design, the survey population is derived from the 2005’s agricultural census of Korea. And coefficient of variation(CV) is estimated from the current livestock production cost survey data, and the estimated CV’s are used to find the optimal sample size which satisfies the predetermined precision of estimation. In order to save the enumeration cost, the agriculture enumeration districts are used as a primary sampling unit(psu). Final sample is selected by double sampling. Also, we propose the estimator which is able to reflect the change of the population of livestock production households.

• Journal of Korean Society of Forest Science
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• v.109 no.3
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• pp.291-299
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• 2020

The purpose of this study was to propose the most cost-effective sampling method, by analyzing the cost of forest resource investigation per sampling method for the planned harvesting area of in Chunyang-myeon, Byeonghwa-gun, Gyeongsangbuk-do, Korea. For this study, three sampling methods were selected: random sampling method, systematic sampling method, and line transect method. For each method, sample size, hourly wage, number of sample points, survey time, travel time, the sample error rate of the estimated average volume, and the desired sampling error rate were used to calculate the cost of forest resource inventories. Thus, 10 sampling points were extracted for each sampling method, and the factors required for cost analysis were calculated via a field survey. As a result, the field survey cost per ha using the random sampling method was found to be have the lowest cost, regardless of the desired sampling error rate, followed by the systematic sampling method, and the line transect method.

• Proceedings of the Korean Association for Survey Research Conference
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• 2001.06a
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• pp.45-56
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• 2001

In this paper, we conducted an empirical study to investigate the design and weighting effects on descriptive and analytic statistics. We compared the regression models using the design-based approach and the generalized estimating equations(GEEs) approach with the model-based approach through the design and weighting effects analysis.

• Survey Research
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• v.6 no.2
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• pp.1-32
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• 2005

The accuracy of exit poll mainly depends on the sampling method of voting places. For exit poll, we propose a probability sampling method of selecting voting places as an alternative to the bellwether polling place sampling. Through an empirical study based on the 2004 general election data, the efficiency of the suggested systematic sampling from ordered voting places was evaluated in terms of mean prediction error and it turns out that the proposed sampling method outperformed the bellwether polling places sampling. We also calculated the variance of estimator from the proposed sampling, and considered the sample size problem to guarantee the target precision using the design effect of the proposed sample design.

• Korean journal of applied entomology
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• v.40 no.2
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• pp.105-109
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• 2001

Dispersion pattern of the citrus red mite (CRM), Panonychus citri (McGregor) was determined to develop a monitoring method in the satsuma mandarin fields, Citrus unshiu L., in Jeju-do, during 1999 and 2000. CRM population was sampled by collecting leaves. Taylor's power law provided better description of mean-variance relationship for the dispersion indices compared to Iwao's patchiness regression. Slopes and intercepts of Taylor's power law from leaf samples did not differ among surveyed groves. Fixed-precision levels (D) of a sequential sampling plan were developed using Taylor's power law parameters generated from all motile stages of CRM in leaf sample. This sampling plan for leaf sample estimate was tested with resampling validation for sampling plan using 4 independent data sets. Resampling simulation analysis demonstrated that actual fixed-precision level values were better than desired D values of 0.20, 0.25 and 0.30. Required numbers for tree sampling at the density of more than 7 mites per tree were fewer than 18.

• The Korean Journal of Applied Statistics
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• v.6 no.1
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• pp.145-162
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• 1993

We review sampling schemes on successive occasions with partial replacement of units and propose a Rao-Hartley-Cochran(RHC) type's sampling scheme over two successive occasions with probability proportionate to observations on the previous occasion. For comparison of the reviewed and proposed sampling schemes, optimal estimator of population mean on second occasion and its variance are derived. The relative efficiency of the proposed sampling scheme is compared with other equal and unequal probability sampling scheme by theoretical and numerical simulation study. For simulation study, three artificial populations are generated by a time series model. It is observed that RHC type's sampling scheme has small variance and deviation in general.

• Proceedings of the Korean Association for Survey Research Conference
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• 2000.06a
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• pp.113-132
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• 2000

본 연구에서 구현하 SLWES(Sampling Learning Web Expert System)은 인터넷 환경에서 표본조사의 학습과 실제 표본조사 자료로부터 모수를 추정할 수 있도록 웹 프로그래밍 기술과 HTML을 결합하여 학습시스템과 통계계산 시스템, 그리고 전문가시스템으로 구성된 표본조사 학습전문가 시스템이다. SLWES는 표본조사에 대하여 전문 지식이 없거나 통계패키지 사용에 익숙하지 않은 비전문가들에게 표본추출법, 무수측정 표본크기 결정 등 표본조사에 대한 이론 학습과 실습의 기회를 인터넷 환경에서 직접 제공함으로써 사용자의 지식에 따라 표본조사론에 대해 체계적이고 효과적으로 학습할 수 있는 시스템이다. 또한 SLWES는 실제 표본조사의 표본추출에 적용될 수 있고 수집된 자료로부터 모수를 추정할수 있으므로 표본조사에 활용될 수 있다.