• Journal of the Korean Statistical Society
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• v.9 no.2
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• pp.213-217
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• 1980

This paper aimed at studying an efficient sampling design of the survey for non-consignment fishery products including both marine fisheries and seaculture. An analysis was done on the relationship between precision and sample size. On the basis of the analysis, the sample size was determined to be 1,080 fishery house holds with the expected precision of 4%-5%. The molluscs and seaculture were recognized to be correlated with the non-consignment products. An attempt was made to investigate the coverage of the fish kinds by the sample about 100 fish kinds were found in the 80 selected sample villages, whereas the population includes about 120 in total. This shows that the sample represents the population with satisfaction.

• Survey Research
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• v.9 no.2
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• pp.119-149
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• 2008

In this changing, complex modern society, as one-person households, dual income households and the elderly population increases and the survey environment gets worse, the past 'method' in which high costs and much time are needed, should face the environmental change. When considering the fact that developed countries in Northern Europe such as Denmark and Finland use administrative data for the Censuses, Korea should carry out further research to use resident registration administrative data in the Registration Census. Based on administrative data, the Registration Census is expected to reduce survey costs and to increase the accuracy and timeliness of surveys. Moreover, a wide variety of statistical demand will be satisfied by producing advanced statistics through the links among administrative data. The paper examines the difference when linking both resident registration administrative data and the results of 2005 Population Census, with a view to improving the Population Census method and preparing for the information age. Also this paper presents some proposals for future Population Censuses. With confidentiality given the top priority, this paper examines the link with matching value of ages and genders at Haeundae-gu, Busan and Boeun-gun, Chungbuk for pragmatic research. Hoenam-myeon, Boeun-gun, Chungbuk marks a low matching rate. Focused on Hoenam-myeon data, this research directly compares the results of 2005 Population Census with resident registration administrative data. Births, deaths, out-migrations and in-migrations from resident registration administrative data as of November 1st 2005 are used especially to increase comparison with the results of 2005 Population Census.

• Journal of the Korean Data and Information Science Society
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• v.24 no.4
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• pp.701-712
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• 2013

The e-learning industry status survey statistic provides information about the actual conditions of supply and demand of the e-learning industries. NIPA (National IT Industry Promotion Agency) has published the annual report of the survey results since 2004. Due to the 9th version of the KSIC (Korean standard industrial classification) revised in 2008, a refinement of the sampling design for the survey becomes necessary, especially that for the business demand sector. This article, based on the 9th revision of the KSIC, constructs a stratification of the target population used for the e-learning industry status survey on the business demand sector. Classification of strata in the business population is based on the industrial type and employment scale of business. Under the stratified population, we design a sampling scheme by using the power allocation method that enables us to satisfy a target coefficient of variation of each industrial stratum. In order to secure an accurate survey results based on the proposed sampling design, we consider the problem of calculating the design weights, derivation of parameter estimators, and formulas of their standard errors.

• Journal of Practical Engineering Education
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• v.13 no.2
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• pp.393-403
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• 2021

The purpose of this study is to propose a method of designing a systematic panel survey at the institutional level to lay the foundation for data-based decision-making using vocational training teachers and instructors as the population. In this study, the target population and sampling frame, which are the main elements necessary for planning a panel survey, are proposed. Also based on expert advice and empirical data analysis, the sampling unit and sampling method taking into account the outer and inner variables are presented, comprehensively considering the representativeness of data, the efficiency and sustainability of data collection. As a result of the study, with the unit of the panel as a vocational training institution, a two-stage stratified proportional sampling plan is proposed so that the institution selected as the panel and the vocational training teachers and instructors belonging to the institution can participate in the survey. Based on this, implications for the panel survey sample design are presented.

• Korea journal of population studies
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• v.19 no.1
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• pp.73-92
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• 1996

There are basically three approaches of surveys on the economically active population, namely Labor Force Approach (or Current Status Approach), Usual Status Approach, and Gainful Worker Approach. The selection of an approach among these approaches to be applied to a survey or population census should take into considerations the purpose and background of the survey or the census and the socio-economic situation of a country. In the Korean Population and Housing Census series which have been taken almost every five years since its first round in 1925, a sample survey on the economically active population has been adopted since the 1960 round of census. Even if the labor force approach continued to be applied to the censns prior to 1980, the approach has been different from one round to another in recent rounds. It may be suggested that the labor force approach continue to be adopted for the Korean Population and Housing Census for the following reasons: 1) the proportion of seasonal workers to the total workers is very small, 2) the proportion of population whose type of activity for a specific duration is different from that for one year is small, 3) the approach for the census should be the same as that for a variety of sample surveys on the economically active population which adopt the labor force approach, since the census functions as a population as well as a bench mark for those sample surveys, 4) an application of labor force approach will facilitate international comparisons since most of countries that conduct a population census adopt this approach, 5) the labor force approach can improve the reliability of results, thanks to its short reference period, etc.

• Korea journal of population studies
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• v.20 no.1
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• pp.5-25
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• 1997

The historical study reveals that our ancestors had maintained a system which could produce data on the number of population and households as well as on their characteristics. For example, such data on age structure of the population, number of births, number of deaths by age & sex, number of in & out migrants were found in an historical document for the year 755. The main purposes of maintaining the system at that time were taxation and conscription. As the system evolves, another function of identifying the legal status of people was also added. Looking into the figures for those days reveals that ommission rates of the number of population and households were high. Thus, in an effort to obtain a reliable data, the annual population survey system was introduced as of 1 September 1896. This date is now cerebrated as the Statistics Day. Since then, the survey system has been diversified. At the present time, there are three major data sources which produce the statistics on population and households: Civil Registration System (vital statistics), Resident Registratiton System (migration statistics) and Population Census. However, these three systems are found to have some problems to produce the accurate data. There are some inherent problems in the registration systems such as problems in its coverage, accuracies in contents and timeliness in reporting the vital events and publishing the results. The population census has also non-sampling errors such as errors in coverage, response and non-response. Apart from the above mentioned problems, there are also conflicting problems arised from having different three data source. We can find some overlapping problems in laws and difficulties in comparative studies between regions. In the future, these problems should be taken into consideration for the improvement of the quality of statistics on population and households.

• Journal of the Korean Data and Information Science Society
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• v.18 no.2
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• pp.419-427
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• 2007

Recently, Korean National Statistical Office submits the results of population projections for Korea from 1960 to 2050 year. The purpose of this paper is to suggest the reasonable assumptions for the survey of population, and then to detect the errors of the surveyed population (1960-2005) on Korean Information Statistical System.

• Survey Research
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• v.5 no.1
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• pp.1-26
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• 2004

The aim of this study lies in answering the question "How to form weighting cells to enhance sample representativeness in telephone, Internet and mobile surveys\ulcorner". For this, we explored 2% raw data of Year 2000 Population and Housing Census of Korea looking for meaningful patterns for ownership of telephones, the usage of Internet and/or mobile phones. We found that telephone coverage rates vary significantly by household size; 84.6% for one member households, contrasting 98.5% for two-or-more member households. Thus, telephone survey samples need to be weighted differently in sub-groups by household size for proportional representation of target population. Searching socio-demographic factors influencing the use of Internet by C5.0 tree models, we found that education levels and the occupation (or housing type, the automobile ownership) are two most important factors in addition to gender and age. Thus, surveyor might form weighting cells by such factors at the stage of post-stratification or set quotas, a priori, proportional to size of the cells by such factors. For mobile surveys, we approached similarly and found that education levels and the occupation (or the automobile ownership, marriage status) are two additional factors that may be used in forming weighing cells or in setting quotas for cells.

• Journal of The Korean Astronomical Society
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• v.41 no.1
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• pp.7-15
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• 2008

We carried out a set of simulations to reproduce the performance of wide-field NEO surveys based on the revised population model of Near Earth Objects (NEOs) constructed by Morbidelli (2006). This is the first time where the new model is carefully compared with discovery statistics, and with the exception of population model, the simulation is identical to the procedure described in Moon et al. (2008). Our simulations show rather large discrepancy between the number of NEO discoveries made by the actual and the simulated surveys. First of all, unlike Bottke et al. (2002)'s, Morbidelli (2006)'s population model overestimates the number of NEOs. However, the latter reproduces orbit distributions of the actual population better. Our analysis suggests that both models significantly underestimate Amors, while overestimating the number of Apollos. Our simulation result implies that substantial modifications of both models are needed for more accurate reproduction of survey observations. We also identify Hungaria region (HU) to be one of the most convincing candidates that supply a large fraction of asteroids to the inner Solar System.

• Survey Research
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• v.7 no.2
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• pp.53-69
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• 2006

Weights can be made and imposed in both sample design stage and analysis stage in a sample survey. While in design stage weights are related with sample data acquisition quantities such as sample selection probability and response rate, in analysis stage weights are connected with external quantities, for instance population quantities and some auxiliary information. The final weight is the product of all weights in both stage. In the present paper, we focus on the weight in analysis stage and investigate the effect of such weights imposed on the weighted mean when estimating the population mean. We consider a finite population with a pair of fixed survey value and weight in each unit, and suppose equal selection probability designs. Under the condition we derive the formulas of the bias as well as mean square error of the weighted mean and show that the weighted mean is biased and the direction and amount of the bias can be explained by the correlation between survey variate and weight: if the correlation coefficient is positive, then the weighted mein over-estimates the population mean, on the other hand, if negative, then under-estimates. Also the magnitude of bias is getting larger when the correlation coefficient is getting greater. In addition to theoretical derivation about the weighted mean, we conduct a simulation study to show quantities of the bias and mean square errors numerically. In the simulation, nine weights having correlation coefficient with survey variate from -0.2 to 0.6 are generated and four sample sizes from 100 to 400 are considered and then biases and mean square errors are calculated in each case. As a result, in the case or 400 sample size and 0.55 correlation coefficient, the amount or squared bias of the weighted mean occupies up to 82% among mean square error, which says the weighted mean might be biased very seriously in some cases.