• International Journal of Internet, Broadcasting and Communication
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• 제16권1호
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• pp.314-320
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• 2024

Objectives: This study aimed to identify the prevalence of falls in community-dwelling older adults and to identify associated factors using the 2019 Community Health Survey. Methods: The original data was from the 2019 Community Health Survey, and the study sample comprised 1,642 older adults aged 65 years and older in Jeju province. Data collection was conducted from August 16 to November 20, 2019, through an interview done by a trained investigator. Respondents were queried about demographic characteristics, riding bicycles, hospital treatment due to an accident or poisoning in the previous year, fall experiences in the past year, fear of falling, self-management status, and pain and discomfort. Multivariate logistic regression analysis was used to evaluate for associations between potential risk factors and falls. Results: The prevalence of falls in this community-dwelling older adults was 13.1%. Falls were associated with riding bicycles (odds ratio = 4.7; 95% confidence interval: 2.26-9.81), fear of falling (odds ratio = 0.3; 95% confidence interval: 0.24-0.49), hospital treatment due to an accident or poisoning in the previous year (odds ratio = 7.8; 95% confidence interval: 5.02-12.19), self-management status (odds ratio = 0.6; 95% confidence interval: 0.34-0.89), and pain and discomfort (odds ratio = 0.6; 95% confidence interval: 0.40-0.87). Conclusions: We found that the prevalence of approximately about 13% of older adults living in a community has experienced falls. Based on the results of the study, we provided primary data to develop the care management intervention program to prevent falls and avoid risk factors that cause falls in community-dwelling older adults.

• Communications for Statistical Applications and Methods
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• 제27권1호
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• pp.47-64
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• 2020

In this paper, we derive some estimators of the scale parameter of the exponentiated half-logistic distribution based on the multiply Type-I hybrid censoring scheme. We assume that the shape parameter λ is known. We obtain the maximum likelihood estimator of the scale parameter σ. The scale parameter is estimated by approximating the given likelihood function using two different Taylor series expansions since the likelihood equation is not explicitly solved. We also obtain Bayes estimators using prior distribution. To obtain the Bayes estimators, we use the squared error loss function and general entropy loss function (shape parameter q = -0.5, 1.0). We also derive interval estimation such as the asymptotic confidence interval, the credible interval, and the highest posterior density interval. Finally, we compare the proposed estimators in the sense of the mean squared error through Monte Carlo simulation. The average length of 95% intervals and the corresponding coverage probability are also obtained.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제11권2호
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• pp.110-115
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• 2008

목 적: 장중첩증의 일차적인 치료로 사용되는 비수술적 관장 정복은 장천공, 쇼크 그리고 복막염 등과 같은 심각한 합병증과 불필요한 스트레스 및 과도한 방사선 노출의 위험이 있다. 본 연구에서는 무리한 비수술적 정복의 시도를 피하기 위하여 장중첩증 환자의 임상 양상 및 검사 소견 중 비수술적 정복 실패를 예측할 수 있는 인자를 파악하고자 하였다. 방 법: 고려대학교 의료원 안산병원에서 1998년 3월에서 2006년 7월까지 장중첩증으로 진단되어 치료받았던 환자 314명 중 비수술적 정복이 시도되었던 300명을 대상으로 하였다. 비수술적 정복의 성공 군과 실패군으로 나누어 성별, 연령, 임상증상 및 이학적 소견 그리고 증상의 시작에서 비수술적 정복술을 시도하기까지의 시간과 비수술적 정복 실패와의 연관성을 분석하였다. 결 과: 비수술적 정복 실패 군의 경우 성공 군에 비해 연령이 어렸고(12.3${\pm}$17.2개월 vs 18.0${\pm}$15.8개월, p=0.03), 정복 시도까지의 시간 경과가 길었으며(33.6${\pm}$29.0시간 vs 21.5${\pm}$20.3시간, p<0.01), 구토, 기면은 많았음(p<0.01)에 비해 복통이나 보챔은 적었다(p<0.01). 이러한 인자들의 다중회귀분석에서 비수술적 정복 실패와 연관된 인자는 6개월 미만 연령(odds ratio: 2.5, 95% confidence interval: 1.2~5.2, p=0.01), 24시간 경과(odds ratio: 2.1, 95% confidence interval: 1.2~4.2, p=0.03), 혈변(odds ratio: 4.8, 95% confidence interval: 1.9~12.2, p<0.01), 기면(odds ratio: 3.4, 95% confidence interval: 1.1~10.4, p=0.04), 복통 또는 보챔(odds ratio: 0.2, 95% confidence interval: 0.1~0.4, p<0.01)이었다. 결 론: 장중첩증에서 6개월 미만 어린 연령, 혈변이나 기면의 소견, 증상 시작 24시간이 경과된 경우 비수술적 정복 실패의 가능성이 많으므로 이러한 사항을 충분히 고려하여 시행 여부를 결정하는 것이 좋겠다.

• Genomics & Informatics
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• 제18권4호
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• pp.45.1-45.5
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• 2020

With the ongoing rise of coronavirus disease 2019 (COVID-19) pandemic across the globe, interests in COVID-19 antibody testing, also known as a serology test has grown, as a way to measure how far the infection has spread in the population and to identify individuals who may be immune. Recently, many countries reported their population based antibody titer study results. South Korea recently reported their third antibody formation rate, where it divided the study between the general population and the young male youths in their early twenties. As previously stated, these simple point estimates may be misinterpreted without proper estimation of standard error and confidence intervals. In this article, we provide an updated 95% confidence intervals for COVID-19 antibody formation rate for the Korean population using asymptotic, exact and Bayesian statistical estimation methods. As before, we found that the Wald method gives the narrowest interval among all asymptotic methods whereas mid p-value gives the narrowest among all exact methods and Jeffrey's method gives the narrowest from Bayesian method. The most conservative 95% confidence interval estimation shows that as of 00:00 November 23, 2020, at least 69,524 people were infected but not confirmed. It also shows that more positive cases were found among the young male in their twenties (0.22%), three times that of the general public (0.051%). This thereby calls for the quarantine authorities' need to strengthen quarantine managements for the early twenties in order to find the hidden infected people in the population.

• Journal of the Korean Data and Information Science Society
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• 제13권2호
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• pp.355-363
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• 2002

Using the Buckley-James method, we construct bootstrap confidence intervals for the regression coefficients under the censored data. And we compare these confidence intervals in terms of the coverage probabilities and the expected confidence interval lengths through Monte Carlo simulation.

• 대한안전경영과학회지
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• 제10권2호
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• pp.205-210
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• 2008

The research interprets the principles of sampling error design for quality statistics models such as hypothesis test, interval estimation, control charts and acceptance sampling. Introducing the proper discussions of the design of significance level according to the use of hypothesis test, then it presents two methods to interpret significance by Neyman-Pearson and Fisher. Second point of the study proposes the design of confidence level for interval estimation by Bayesian confidence set, frequentist confidential set and fiducial interval. Third, the content also indicates the design of type I error and type II error considering both productivity and customer claim for control chart. Finally, the study reflects the design of producer's risk with operating charistictics curve, screening and switch rules for the purpose of purchasing and subcontraction.

• Journal of the Korean Data and Information Science Society
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• 제21권3호
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• pp.493-502
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• 2010

환율의 신뢰구간을 예측하기 위해 가장 중요한 요인은 분포의 추정이다. 그러나 시계열 자료의 분포를 추정하는 것은 많은 어려움이 따른다. 본 연구에서는 변동률 합의 분포를 비모수기법 중의 하나인 블록화 붓스트랩 방법을 사용하여 추정한다. 따라서 좀 더 쉽고 정확한 환율의 장단기 신뢰구간 예측 모형을 제시한다.

• 산업공학
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• 제22권3호
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• pp.214-222
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• 2009

In the early design stage, system reliability must be estimated from life testing data at the component level. Previously, a point estimate of system reliability was obtained from the unbiased estimate of the component reliability after assuming that the number of failed components for a given time followed a binomial distribution. For deriving the confidence interval of system reliability, either the lognormal distribution or the normal approximation of the binomial distribution was assumed for the estimator of system reliability. In this paper, a new estimator is used for the component level reliability, which is biased but has a smaller mean square error than the previous one. We propose to use the beta distribution rather than the lognormal or approximated normal distribution for developing the confidence interval of the system reliability. A numerical example based on Monte Carlo simulation illustrates advantages of the proposed approach over the previous approach.

• International Journal of Quality Innovation
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• 제6권2호
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• pp.31-45
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• 2005

The target costing technique, mathematically discussed by Sauers, only uses the $C_p$ index along with Taguchi loss function and ${\bar{X}}-R$ control charts to set up goal control limits. The new specification limits derived from Taguchi loss function is linked through the $C_p$ value to ${\bar{X}}-R$ control charts to obtain goal control limits. This study further considers the reflected normal loss function as well as the $C_{pk}$ index along with its lower confidence interval in forming goal control limits. With the use of lower confidence interval to replace the point estimator of the $C_{pk}$ index and reflected normal loss function proposed by Spiring to measure the loss to society, this modified and improved target costing technique would become more robust and applicable in practice. Finally, an example is provided to illustrate how this modified and improved target costing technique works.

• Journal of the Korean Statistical Society
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• 제27권3호
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• pp.359-368
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• 1998

Let ξ$_{p}$(z$_{0}$) be the pth quantile of the distribution of the survival time of an individual with time-invariant covariate vector z$_{0}$ in the additive risk model. We propose an estimator of (ξ$_{p}$(z$_{0}$) and derive its asymptotic distribution, and then construct an approximate confidence interval of ξ$_{p}$(z$_{0}$) . Simulation studies are carried out to investigate performance of the proposed estimator far practical sample sizes in terms of empirical coverage probabilities. Also, the estimator is illustrated on small cell lung cancer data taken from Ying, Jung, and Wei (1995) .d Wei (1995) .