• 대한수학교육학회지:수학교육학연구
• /
• 제21권1호
• /
• pp.17-32
• /
• 2011

본 연구에서는 예비교사들의 통계적 표집에 대한 이해를 조사하였다. 먼저 선행 연구를 바탕으로 표집의 이해와 관련된 주요 주제를 표본의 대표성, 표집 변이성, 표집분포로 구분하고, 각각의 주요 주제에 대한 세부 개념 요소들을 선정하였다. 이에 대한 예비교사들의 이해를 조사한 결과 대부분의 예비교사들이 편의를 일으키지 않는 무작위 추출이 표집방법으로 적절함을 이해하고 있었으나 약 64%의 예비교사들만이 표본을 모집단의 준비례적 축소버전으로 인식하고 있었다. 표집에서 표본이 모집단에서 차지하는 비율보다 표본의 크기 자체가 중요함을 인식하는 예비교사는 극소수에 불과했으며, 조사 대상의 절반에 해당하는 예비교사들만이 신뢰할 수 있는 결과를 도출하기 위해 전체 표본의 크기가 아니라 표집 횟수가 중요함을 인식하였다. 그리고 표집분포는 모집단 분포의 형태와 무관하게 모집단의 평균을 중심으로 대칭적인 형태를 나타낸다는 것을 이해하는 예비교사는 매우 적었다.

• 한국전문물리치료학회지
• /
• 제23권2호
• /
• pp.93-99
• /
• 2016

Background: Parametric statistical procedures are typically conducted under the condition in which a sample distribution is statistically identical with its population. In reality, investigators use inferential statistics to estimate parameters based on the sample drawn because population distributions are unknown. The uncertainty of limited data from the sample such as lack of sample size may be a challenge in most rehabilitation studies. Objects: The purpose of this study is to review the bootstrapping method to overcome shortcomings of limited sample size in rehabilitation studies. Methods: Articles were reviewed. Results: Bootstrapping method is a statistical procedure that permits the iterative re-sampling with replacement from a sample when the population distribution is unknown. This statistical procedure is to enhance the representativeness of the population being studied and to determine estimates of the parameters when sample size are too limited to generalize the study outcome to target population. The bootstrapping method would overcome limitations such as type II error resulting from small sample sizes. An application on a typical data of a study represented how to deal with challenges of estimating a parameter from small sample size and enhance the uncertainty with optimal confidence intervals and levels. Conclusion: Bootstrapping method may be an effective statistical procedure reducing the standard error of population parameters under the condition requiring both acceptable confidence intervals and confidence level (i.e., p=.05).

• 응용통계연구
• /
• 제32권3호
• /
• pp.375-389
• /
• 2019

패널 자료는 자료가 축적되는 만큼 그 가치가 증대된다. 이와 동시에 장기추적에 따른 표본이탈은 자료의 신뢰성을 떨어뜨린다. 국내 외 대부분의 패널조사에서 가중값 보정을 통해 표본 이탈 문제를 해결하고 있다. 본 논문에서는 패널자료에서 차수별 응답여부에 따라 연속 응답 그룹과 비연속 응답 그룹으로 나누고, 비연속 응답 그룹에 대한 적정 가중값 산출방법을 검토하였다. 연속/비연속 응답그룹을 구분하여 비연속 응답 그룹의 응답자 특성을 반영한 복합추정 방식의 가중값 작성방법을 제안하고, 그룹의 구분 없이 작성하였던 기존의 가중값 작성방법과 새로 제안한 복합추정 방식의 가중값 산출방법의 효율성을 모의실험과 실증분석을 통해 살펴보았다. 결과적으로 새로 제안한 복합추정 방식의 가중값 산출방법은 기존 방법 보다 편향을 대폭 감소시킴을 모의실험을 통해 볼 수 있었다. 한편, 제시한 가중값 작성방법을 한국고용정보원 고령화연구패널에 적용한 결과도 제시하였다.

• 보건행정학회지
• /
• 제23권2호
• /
• pp.152-161
• /
• 2013

Korea has a single National Health Insurance program and all citizens are covered under this program, accounting 97% of the population, approximately 50 million people. Claims submitted by Health care providers are reviewed by Health Insurance Review and Assessment (HIRA) for the reimbursement. HIRA database contains not only individual beneficiary's information, but also healthcare service information such as diagnosis, procedures, prescriptions and tests for them. HRA database has gained attention as importance source for research due to its rich healthcare information and the demand of HIRA database has increased. Due to its tremendous size, however, researchers have had problems in accessing the database to conduct research. To meet this demand, we conducted a study to develop the inpatient sample data from HIRA database for research. This study has two purposes: 1) to determine a needed sample size; 2) to test reliability and validity of the sample data. We determined an adequate sample size to ensure representativeness and generality with additional consideration for convenience of calculation. The minimum sample size was 729,904 for the generality, and 488,861 for representativeness. After considering the convenience of calculation, our final sample size was 13% of the population, which was about 7.7 million beneficiaries. Age (5 years interval) and gender were used as stratification variables for sampling. In order to examine whether this sample data appropriately reflect population, we tested the reliability and validity of the sample data. From the sample data, we computed average expenditure of total claims per inpatient for 2011, frequency of top 30 disease, estimation of the number of stroke patients from the sample data, and then compared them to those from the population. Results confirmed reliability and validity of the sample data.

• Nuclear Engineering and Technology
• /
• 제54권10호
• /
• pp.3788-3794
• /
• 2022

The possibility of denuclearization of the Korean Peninsula has been continuously debated, and the initiative participation of the Republic of Korea has necessitated preemptive measures against neighboring countries. In this study, we present a proposal for formulating a site survey plan when the amount of site information provided is insufficient and the accuracy of the information is not guaranteed. Considering a case wherein "a soil sample analysis is used to determine the presence or absence of nuclear activity" in a radiochemical laboratory, which is a typical key facility for denuclearization, the optimal soil sample collection plan is designed based on international guidelines and public information. In the event of denuclearization, a scenario that is not based on the expertise of the sample collector is set, and the data quality objective (DQO) process is applied to ensure reality. Consequently, the primary sample collection points can be derived in consideration of accessibility, and the sample collection scale can be adjusted according to the cost. By applying the DQO process to ensure sample representativeness and reality, reliable and resource-efficient soil sample collection can be achieved in radiochemical laboratories and other denuclearization facilities.

• The Journal of Asian Finance, Economics and Business
• /
• 제8권3호
• /
• pp.1231-1240
• /
• 2021

A shift in perspective from standard finance to behavioral finance has taken place in the past two decades that explains how cognition and emotions are associated with financial decision making. This study aims to investigate the influence of various psychological factors on investment decision-making. The psychological factors that are investigated are differentiated into two aspects, cognitive and emotional aspects. From the cognitive aspect, we examine the influence of anchoring, representativeness, loss aversion, overconfidence, and optimism biases on investor decisions. Meanwhile, from the emotional aspect, the influence of herding behavior on investment decisions is analyzed. A quantitative approach is used based on a survey method and a snowball sampling that result in 165 questionnaires from individual investors in Yogyakarta. Further, we use the One-Sample t-test in testing all hypotheses. The research findings show that all of the variables, anchoring bias, representativeness bias, loss aversion bias, overconfidence bias, optimism bias, and herding behavior have a significant effect on investment decisions. This result emphasizes the influence of behavioral factors on investor's decisions. It contributes to the existing literature in understanding the dynamics of investor's behaviors and enhance the ability of investors in making more informed decision by reducing all potential biases.

• 한국조사연구학회지:조사연구
• /
• 제9권3호
• /
• pp.55-69
• /
• 2008

이제까지 우리나라에서 전화조사를 위한 표본목록은 거의 대부분 전화번호부로부터 나왔다. 그러나 전화번호부의 모집단 포함률이 너무 떨어진다는 지적이 있어 대응수단으로 국제적 기준인 RDD(random digit dialing, 임의번호걸기)가 구현된 바 있다. 2007년 12월의 17대 대통령선거에 대한 예측을 위해 투표일을 $5{\sim}6$일 앞서 실시된 KBS MBC 전화조사는 표본을 반씩 나누어 절반은 RDD로, 나머지 절반은 전화번호부에서 응답자 표본목록을 추출하였다. 이 사례연구는 KBS MBC 전화조사의 RDD 표본과 전화번호부 표본을 대비시켜 공통점과 상이점을 살펴본 것이다. 향후 수년 동안 전화번호부 표본과 RDD 표본이 공존할 것으로 예상되는 상황에서, 이 연구결과가 두 방식의 비교에 시사점을 제시할 것으로 기대한다.

• Asian Journal for Public Opinion Research
• /
• 제3권3호
• /
• pp.111-130
• /
• 2016

Researchers have been perplexed by the issue of unit nonresponse since the beginning of practicing survey research and have been attentive to the causes that lead to the occurrence of unit nonresponse as well as the impact of unit nonresponse. However, because researchers have little to no information regarding unit nonrespondents, it is unlikely that they are able to examine the differences between participants and nonrespondents to estimate the loss of representativeness in the final sample compared with the target population. Therefore, the lack of information regarding the absentees complicates addressing the unit nonresponse bias in a satisfactory manner. Therefore, the purpose of this study was to determine the demographic characteristics and political attitudes of nonrespondents by relying on information provided by their spouses, which was obtained through a telephone survey conducted in Taiwan. It is found that demographic variables as well as political attitudes are related to the likelihood of an individual becoming a unit nonrespondent in telephone surveys.

• 한국의류산업학회지
• /
• 제13권4호
• /
• pp.590-599
• /
• 2011

The purpose of this study is to classify body types into different groups based on 3D scanned data, and identify the representative body shapes that most frequently appear in the groups. A high frequency range was defined based on body measurement data, and representative shapes were identified based on body scan data of women aged 18-24. The major findings of this study are as follows. First, the three typical types of height, bust and drop mixes among Korean women aged 18-24 are as follows:) 155-88-N,) 160-82-A, and 165-85-A. Regarding the body type, the A and N types frequently appeared, while the H type was rare. Second, among the subjects of the high-frequency groups, upright bodies were selected as sample models and were used for morphing. An adjustment was made to the morphing results to reflect the body characteristics of the sample models evenly. Third, to verify the morphing results, the body sizes of the sample models and the created models were compared. The result showed that, the sizes were close to the average size of the sample models. Fourth, to verify whether the morphing processes adequately reflected the features of the body shapes, cross-section models of key body parts were made and the degree of representativeness was determined.

• Asian Journal for Public Opinion Research
• /
• 제9권3호
• /
• pp.240-265
• /
• 2021

Public services need to be evaluated regularly to identify areas that need further improvement. Data collection via Twitter is affordable and timely, so it has the potential to be utilized to evaluate the quality of public service. This study utilizes tweets mentioning three service units of the provincial government of Jakarta and applies both sentiment analysis and topic classification to predict a rating/score of public service quality. The research goal is to examine if the evaluation of public services based on social media data is possible. The findings indicate that the use of Twitter has an advantage in terms of sample size and variety of opinions. Tweets can be translated into scores as well. Nonetheless, the representativeness issue and the predominance of complaint tweets can affect the reliability of the results.