• Journal of the Korean Society of Radiology
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• v.15 no.7
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• pp.1015-1020
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• 2021

This study retrospectively analyzed the test results of 113 healthy postmenopausal women without special diseases among patients who visited a medical institution in Busan from January 2020 to June 2021. The purpose of the study was to investigate the effect of BMI (Body Mass Index) on bone density in menopause women, the analysis of the lumbar and femur of patients with low weight (BMI<18.5) showed a significant probability (p-value) of 0.000, and the normal weight (18.5≦BMI<23.0) of the femur. In overweight (23.0≦BMI<25.0), the significance probability (p-value) of the lumbar region was 0.021 and the significance probability (p-value) of the femur was 0.034, confirming the correlation. However, in patients with high obesity (30.0≦BMI<40.0), the p-value of the lumbar region was 0.127, and the p-value of the femur was 0.093, indicating that there was no correlation between BMI and bone density.

• The Korean Journal of Applied Statistics
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• v.15 no.1
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• pp.1-8
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• 2002

Categorizing prognostic factors is very useful for a disease diagnosis, determination of treatment and study eligibility criteria. Methods often used to categorize factors are to select a cutpoint by biological theory, by graphical examination, by the minimum p-value approach. The last method involves multiple testing, and several methods for adjusting p-values have been developed. This study determines the cutpoint of tumor size to separate patients of high risk of relapse after hepatic resection of hepatocellular carcinoma.

• Applied Biological Chemistry
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• v.48 no.2
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• pp.140-149
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• 2005

In order to examine the changes of commercial value during storage conditions and shelf-life of Chungkookjang, response surface methodology of SAS program was applied to monitor orgenoleptic properties and color changes to determine optimum storage conditions. Lightness (L) value of vacuum-packed Chungkookjang showed under the 1% significance probability with high influence in all conditions such as sterilized temperature, storage time and storage temperature. Redness (a) value of vacuum-packed Chungkookjang was increased during highly sterilized and storage temperatures, and was individually influenced. One of the generally packed sample also showed that significance value was influenced under 10%, during high storage temperature. Yellowness (b) value of vacuum-packed Chungkookjang showed the significance probability under 1% during storage time and temperature, and under 5% during sterilized temperature. Also, stational point showed saddle type in both packaging samples. In case of vacuum-packed Chungkookjang, compatibility of odor was influenced by sterilized temperature under 10% significance probability. But generally packed samples have an effect on storage time under 1% significance probability effect on storage time, and sterilized temperature under 5%. In case of vacuum-packed Chungkookjang, compatibility of taste was highly concerned with storage time under 1% significance probability, whereas generally packed samples were concerned with storage temperature under 5% significance probability. Overall palatability of vacuum-packed samples showed maximum value of 5.15 on sterilized temperature ($61.92^{\circ}C$), storage temperature ($6.79^{\circ}C$) and storage time (56.48 days) during storage.

• Proceedings of the Korean Statistical Society Conference
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• 2002.11a
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• pp.227-230
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• 2002

표본의 크기가 작을 경우에 이항분포의 모수에 대한 신뢰구간을 구하는 대표적인 방법으로는 Clopper-Pearson 방법과 Blyth-Still 방법이 있다. Clopper-Pearson 방법에 의한 신뢰구간은 이항 모수가 포함되는 커버리지 확률이 목표로 하는 신뢰수준보다 상대적으로 크다는 문제점이 있다. Blyth-Still 방법은 이러한 문제점을 개선시켰다. 그러나, Blyth-Still에 의해서 표로 보고된 신뢰구간을 적용할 경우 표본의 크기와 이항 모수의 값에 따라서 커버리지 확률이 목표하는 신뢰수준보다 작은 경우가 발생한다. 그러나, 이는 Blyth-Still 방법 자체의 문제점이 아니며 단지 보고된 표의 유의한 소수점 자릿수와 관계가 있다. 본 논문은 Blyth-Still 방법에 의한 좀 더 정확한 신뢰구간을 제시한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.412-412
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• 2017

강우빈도해석을 위해서는 확률분포선정이 우선적으로 이루어져야 한다. 우리나라에서는 사용상의 편리상, 기존 해석결과와의 연속성 등을 이유로 Gumbel 확률분포가 가장 일반적으로 활용되고 있다. 그러나, 분포형 선정에 따른 확률강수량의 차이가 크게 발생한다는 점에서 단순히 해석상의 편리성을 기준으로 분포형 선정이 이루어지는 것은 바람직하지 않다. 특히, 우리나라에서 강우빈도해석 시 분포형 선정은 형식적인 수준에 그치고 있으며, 주로 KS검정, 검정 등 적합도 검정을 통해 고려된 분포형의 통계적 유의성만을 평가하고 있다. 그러나, 최적 분포형 선정이라는 관점에서 이러한 유의성 검정보다는 정량적인 지표를 기준으로 확률분포형 선정이 이루어지는 것이 적합할 것으로 판단된다. 즉, 자료의 설명력이 가장 우수한 분포를 정량적 지표를 기준으로 추정하는 것이 수문통계학적으로 적합성을 갖는다. 이러한 점에서 본 연구에서는 우도함수, BIC 및 AIC를 기준으로 우리나라 주요 강수지점에서 대해서 최적 분포형을 선정하고, 기존 Gumbel 분포를 기준으로 산정된 확률강수량과의 양적차이를 평가해보고자 한다.

• Journal of the Korean Data and Information Science Society
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• v.27 no.5
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• pp.1317-1325
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• 2016

The purpose of this paper is to explain the factors affecting the wage of the vocational high school graduates. We particularly examine the effectiveness of controlling sample selection bias by employing the Tobit model and Heckman sample selection model. The major results are as follows. First it is shown that the Tobit model and Heckman sample selection model controlling sample selection bias is statistically significant. Hence all the independent variables seem to be statistically consistent with the theoretical model. Second, gender was statistically significant, both in the probability of employment and the wage. Third, the employment probability and wage of Maester high school graduates were shown to be high compared to all other graduates. Fourth, the higher parent's income, the higher are both the employment probability and the wage. Finally, parents education level, high school grade, satisfaction, and a number of licenses were found to be statistically significant, both in the probability of employment and wages.

• Survey Research
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• v.11 no.2
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• pp.97-121
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• 2010

Using the 1998-2004 Health and Retirement Study(HRS), this study explored the determinants of private long-term care insurance(LTCI) ownership and the first home care use. To account for the interaction between LTCI purchase and home care use, this study used two-period utility model as theoretical framework. Discrete time model was used as an empirical model to incorporate the time-dependent feature of LTCI ownership. And this study accounted for the endogeneity of LTCI ownership and home care use by employing full information maximum likelihood estimation. This study indicated insignificant effects of private LTCI ownership and Medicaid eligibility on the home care use. Also, the effects of income and assets on home care utilization were negligible. Those who have poor health condition and who do not have potential informal caregivers were more likely to use home care. For private LTCI ownership, income and assets have positive relationship with LTCI purchase, and poor health status and age were negatively related to LTCI purchase. The elderly living with children and those who have more siblings were less likely to have private LTCI, and those who lived with spouses with no children were more likely to buy private LTCI. Based on the findings, this study provides implications to design long-term care(LTC) policies in the U.S. and to develop LTC planning education programs.

• Communications for Statistical Applications and Methods
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• v.5 no.1
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• pp.85-97
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• 1998

완전확률화모형 및 랜덤화블럭모형하에서의 주요한 다중비교 분석기법들을 시뮬레이션을 이용하여 검토하고자 하였다. 시뮬레이션 결과는 순위변환과 최소유의차검정을 이용한 다중비교 분석기법이 모수적 ANOVA F 검정과 Fisher의 유의차검정, 비모수적 Kruskal-Wallis 검정과 최소유의차검정 및 Friedman 검정과 최소유의차검정을 이용한 분석기법보다 전체실험오차율, 전체실험검정력 및 개별쌍검정력 면에서 상대적으로 뛰어남을 보여준다. 즉 순위변환한 ANOVA F 검정의 전체실험오차율은 명목상의 유의수준을 잘 유지하고 있으며, 전체실험검정력 및 개별쌍검정력은 모수적 ANOVA F 검정과 Kruskal-Wallis 검정 및 Friedman 검정기법보다 전반적으로 우수함을 알 수 있다.

• Journal of Korea Entertainment Industry Association
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• v.15 no.8
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• pp.305-313
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• 2021

This study aimed to discover the satisfaction of physical therapy students' major education and the perception of the occupational value of physical therapists and provided basic data to be used for career guidance of college students majoring in physical therapy. A questionnaire survey was conducted online to collect data on participants' general characteristics, motivation for joining the Department of Physical Therapy, satisfaction with their academic majors, and perception of occupational and social value of physical therapy. Using SPSS version 28, frequency and correlation analyses were undertaken and a Chi-square test performed for 174 respondents. As a result of the study, there was no significant difference in major education satisfaction according to gender and grade with as each p-value .368, .685. There was a significant difference in perception of job value according to gender as a p-value .032, and there was no significant difference in the p-value according to gender of .463. There was no significance difference in social job perception according to gender and grade with as each p-value .483, .077. There was positive correlation with the correlation coefficient of .483 that analyzed the level of perception of occupational value of physical therapists according to satisfaction of major education. In conclusion, students's high satisfaction with their academic majors exhibited considerable correlation with their perceived high occupational value of physical therapy. It is believed that these results can be used in career guidance for college students majoring in physical therapy.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.4
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• pp.35-47
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• 2023

Various single probability distributions have been used to represent time headway distributions. However, it has often been difficult to explain the time headway distribution as a single probability distribution on site. This study used the EM algorithm, which is one of the maximum likelihood estimations, for the parameters of combined mixture distributions with a certain relationship between two normal distributions for the time headway of vehicles. The time headway distribution of vehicle arrival is difficult to represent well with previously known single probability distributions. But as a result of this analysis, it can be represented by estimating the parameters of the mixture probability distribution using the EM algorithm. The result of a goodness-of-fit test was statistically significant at a significance level of 1%, which proves the reliability of parameter estimation of the mixture probability distribution using the EM algorithm.