• The Korean Journal of Applied Statistics
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• v.7 no.2
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• pp.159-171
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• 1994

Some rank score tests are proposed for testing the equality of all sampling distribution functions against umbrella location-scale alternatives in k-sample problem. Only the case of known peak $\ell$ is considered. Under the null hypothesis and a contiguous sequence of unbrella location-scale alternatives, the asymptotic properties of the proposed test statistics are investigated. Also, the asymptotic local powers are compared with each others. The results show that the tests based on the Chen-Wolfe rank analogue statistic are more powerful than others for unequally spaced umbrella location-scale alternatives and robust.

• KDI Journal of Economic Policy
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• v.38 no.1
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• pp.53-70
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• 2016

This paper examines market concentration and its effect on competition in the Chinese commercial banking market. This study also investigates how changes in competition have affected the financial stability of Chinese commercial banks. To test the competitive conditions, we obtained the H statistic of the Panzar-Rosse model from a revenue function equation. The degree of financial stability is estimated by the Z-score formula. The Chinese banking industry has become an increasingly less concentrated market with an increased number of banks. Along with a decreased market concentration, competition in the Chinese banking industry has improved moderately. However, its market structure is still far from a competitive market. An individual bank's ability to earn higher markup or charge a higher net interest margin contributes to its financial soundness, although a higher degree of market concentration may have negative effect on the financial stability of the entire banking system.

• Journal of the Korean Society of Systems Engineering
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• v.15 no.1
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• pp.43-50
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• 2019

Statistical hypothesis tests are important for quantifying answers to questions about samples of data. The Step Process of Statistical Hypothesis Testing; state the null hypothesis, State the alternate hypothesis, State the alpha level, Find the z-score associated with alpha level, Find the test statistic using this formula, If the calculated t distribution value from the data is larger than the t distribution value of alpha level, then you are in the Rejection region and you can reject the Null Hypothesis with ($1-{\alpha}$) level of confidence.

• The Korean Journal of Applied Statistics
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• v.22 no.5
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• pp.911-921
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• 2009

Receiver Operating Characteristic(ROC) and Cumulative Accuracy Profile(CAP) curves are two methods used to assess the discriminatory power of different credit-rating approaches. The points of optimal classification accuracy on an ROC curve and of maximal profit on a CAP curve can be found by using iso-performance tangent lines, which are based on the standard notion of accuracy. In this paper, we offer an alternative accuracy measure called the true rate. Using this rate, one can obtain alternative optimal threshold points on both ROC and CAP curves. For most real populations of borrowers, the number of the defaults is much less than that of the non-defaults, and in such cases the true rate may be more efficient than the accuracy rate in terms of cost functions. Moreover, it is shown that both alternative scores of optimal classification accuracy and maximal profit are the identical, and this single score coincides with the score corresponding to Kolmogorov-Smirnov statistic used to test the homogeneous distribution functions of the defaults and non-defaults.

• Journal of Information Technology Services
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• v.19 no.3
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• pp.35-56
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• 2020

The purpose of this study is to measure corporate personality by analyzing the internal employees' corporate reviews and to identify the impact of the representative corporate personality on the relationship between job satisfaction of internal employees and the turnover rate of the company. To this end, we first created a dictionary of words representing the corporate personality with a Word2vec method based on words explaining five corporate personalities, such as reliability, initiative, practicality, activism, and femininity, obtained from the preceding study. Next, we analyzed reviews which were written by internal employees on their companies to measure the score of corporate personality at a review level, aggregated the review level scores for each company to calculate the company level score of corporate personality, and assigned to each company the corporate personality with the maximum score among the five such scores. Also, job satisfaction and turnover rate were measured from internal employees' corporate evaluation scores and the percentage of former employees of each company who left a review on the company, respectively. This study collected datasets of corporate reviews, employee information, and corporate information from Job-Planet from 2014 to 2017, conducted a technical statistic check and correlation analysis to confirm the suitability of the datasets, and performed linear regression analysis to evaluate the research model and verify hypotheses. As a result of the analysis, the job satisfaction of the internal staff has a significant negative impact on the corporate's turnover rate. In addition, companies having a personality of reliability, initiative and femininity also showed a significant cause-and-effect relationship between job satisfaction and turnover rate and among them, job satisfaction of companies having a personality, initiative, showed a greater impact on turnover rate. In sum, we not only proposed a novel method of measuring corporate personality, but also showed that corporates need to identify its corporate personality and to utilize a different strategy to reduce their employee's turnover rate depending on the corporate personality.

• The Journal of Korean Physical Therapy
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• v.20 no.4
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• pp.21-28
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• 2008

Purpose: We measured the Oswestry Low Back Pain Disability Index (OLBPDI) and related factors in patients with low back pain. Methods: The sample consisted of 50 patients who received physical therapy at the physical therapy units of the Andong Seoul Sintong Clinic, St. Luke Clinic, and Yeongju Seoul Sintong Clinic in Andong and Yeongju city from October, 2007, to February, 2008. The OLBPDI questionnaire was administered by 5 physical therapists as a cross-sectional study. Student's t-test and analysis of variance (ANOVA/Tukey and Scheffe) were used to analyze OLBPDI score differences. We also used nonparametric statistic analysis (Wilcoxon rank sum test, Median test). Pearson correlation analysis (Spearman correlation analysis) was used to analyze the relationship between OLBPDI and the visual analogue scale (VAS). Multiple regression analysis was performed to determine the effects of independent variables on pain scores as defined by the OLBPDI. Results: The average patient age was 37.1 years (range: 18$\sim$78 years old), and time from onset was 21.7 months (1$\sim$180). OLBPD and VAS scores were 12.70 (3.0$\sim$28.0) and 5.14 (1$\sim$8), respectively. OLBPDI scores were 14.4 in patients taking medicine and 11.57 in those who did not. There was a statistically significant relationship between OLBPDI and VAS (r=0.54, p=0.0001; r=0.55, p=0.0001 by Spearman coefficient). Gender ($\beta$=6.14, p=0.0124), age ($\beta$=-2.01, p=0.0324), weight ($\beta$=0.31, p=0.0222), time from onset ($\beta$=1.54, p=0.0044), and VAS score ($\beta$=1.59, p=0.0004) were significantly associated with OLBPD by multiple regression analysis. Conclusion: Variables associated with OLBPD were gender, age, weight, time from onset, and VAS score. Collecting information on the pain index using OLBPDI was acceptable to patients with low back pain. Further research should explore the pain index by using larger sample sizes and longer follow-up periods.

• Journal of the Korean School Mathematics Society
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• v.2 no.1
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• pp.145-156
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• 1999

The purpose of this study is to consider students′ scholastic relationship in mathematics between elementary school and middle school from the 3rd grade in elementary school to the 2nd and the 3rd grades in middle school. The following are the results: 1. CONCLUSIONS 1. Students′ present scores are most closely related to those of their previous grade. The data are based on the two groups of the 3rd grade middle school students - one is honhappan(mixed students from different elementary school) and the other shinaepan(the students from the same elementary school in kong ju city). This close relation between present and previous scores in mathematics may well be reasonable since mathematics is systemized hierarchically. Among the score data in elementary school, the scores in the 5th grade are meaningfully related to present score data in mathematics. 2. Two pans (as I mentioned above, honhap and shinae) are divided into groups and their scores are traced from the 3rd grade in elementary school and the data show that the high-levelled students have little changes in their scores, but low-levelled students have dropped radically in their scores from the first grade in middle school. 3. In terms of students′ interests, students who answered, "I′m very interested in mathematics." have no distinguished characteristics in their scores while those who answered, "I have little interest in mathematics" shows a decrease in their scores. 4. Among the reasons for their lack of interests, the replies are "because of exams," "because of teaching methods," and "because of the textbooks." II. Suggestion To compensate the limitation and difficiency of this study, the foll owing is suggested for the following studies related to this one. 1. This study was limited to gathering students′ score data from female students in a small city. For a more accurate statistic a bigger population is needed as well as varied geographical and social economical area is suggested. A good idea is to study homogeneous sex groups as well as heterogeneous sex groups 2. It is easy to find out what grade is closely related to the present scores by statistical analysis, but the reasons for their relationship have to be found out through the following studies 3. There are many studies on cognitive domain in math but it is expected to have more studies on affective domain as well.

• Journal of Korean Public Health Nursing
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• v.18 no.1
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• pp.143-153
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• 2004

The study tried to develop a parent-involvement sex education program and find out its effects for more effective sex education methods for high graders of a primary school. The subjects were recruited from 5 classes of 6th graders in Y Primary School in N city, Kyeonggido province, South Korea. Data collection was done from October 4, 2003 to November 7. The experimental group consisted of 43 students from 3 classes with the help from class teachers and parents' involvement in the program. The control group consisted of 43 students randomly sampled by computer from the other two classes. For the experimental methods, the experimental group was given a parent-involvement sex education program as well as a student sex education program: the control group only received the student sex education program. The results were analyzed according to frequency, percentage, $x^2$-test, fisher's exact test and t-test using SAS program. As a result of the homogeneity test, both the groups proved to be the same (t=-0.29 p=0.77, t=0.49 p=0.62) in preliminary sex-attitude and sex-related communication frequency score. But the two group showed meaningful differences (t=2.52 p=0.01, t=2.04, p=0.04) in preliminary sex-knowledge and sex-related communication quality score. After the sex education programs, the two groups didn't show meaningful statistic differences(t=-0.42 p=0.68, t=1.57 p=0.12) in preliminary sex-knowledge and sex-related communication quality score. But the experimental group was statistically more meaningful (t=2.16 p=0.03, t=4.86 p<0.0001) in the difference of sex attitude and sex-related communication frequency than the control. The parent-involvement sex education program developed in this study was more effective for improving their sex attitude and for increasing the frequency of their sex-related communication with parents than the existing student program. Therefore, for sex education, it's necessary to develop and spread various programs where parents can be involved.

• Journal of Korean Academy of Nursing
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• v.22 no.1
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• pp.68-80
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• 1992

In order to provide data basic to the training of hospice volunteers, this study was carried out to investigate the personal attributes and the Death Orientation of hospice volunteers. 80 hospice volunteers were sampled from those registered on Seoul Catholic Social Service and Korean Association for Volunteers Effort conveniently. Data were gathered from August 16th to October 3rd, 1991. The instrument used for this study was the Death Orientation Questionnaire developed by Thorson and Powell, subjective age and religiosity questionnaire developed by Bell and Batterson, and subjective health criteria developed by Baumann. Data were analyzed using frequency, mean, standard deviation, Chi-square, and t-test by SPSS - program. Result of this study are summarized as follows ; 1. The majority of hospice volunteers perceived younger in their subjective age than their chronological age (65%), Perceived themselves to be healthy subjectively(88.8%), and revealed to have high religiosity score(96.3%) 2. Level of Death Orientation of hospice volunteers was revealed to be moderate.(Mn＝2.06, SD＝0.40, range, 1.45-3.53) Among 25 Death Orientation items, respondents revealed the highest concern over the afterlife (Mn＝3.53, SD＝0.71), revealed the lowest anxiety about not knowing the next world after his or her death(Mn＝1.45, SD＝0.69), and relatively high concern over leaving careful instructions after death (Mn＝2.97, SD＝0.83) Respondents revealed low Death Orientation score(below 1.99) to 12 negative items(2, 3, 5, 6, 7, 9, 14, 17, 18, 19, 20, 22). Thus hospice volunteers seem to be preparing for their own death and shown positive Death Orientation to some items relatively. 3. According to personal attributes (demographic, socioecnomic, and relevant variables) of hospice volunteers, there were no significant statistic differences of Death Orientation score. Thus pre-existing Death Orientation of hospice volunteers and their motive of participation to the hospice service are to be considered important variables influencing the Death Orientation.

• Journal of Korean Neurosurgical Society
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• v.66 no.1
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• pp.95-104
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• 2023

Objective : Hypernatremia is a common complication encountered during the treatment of neurocritically ill patients. However, it is unclear whether clinical outcomes correlate with the severity of hypernatremia in such patients. Therefore, we investigated the impact of hypernatremia on mortality of these patients, depending on the degree of hypernatremia. Methods : Among neurosurgical patients admitted to the intensive care unit (ICU) in a tertiary hospital from January 2013 to December 2019, patients who were hospitalized in the ICU for more than 5 days and whose serum sodium levels were obtained during ICU admission were included. Hypernatremia was defined as the highest serum sodium level exceeding 150 mEq/L observed. We classified the patients into four subgroups according to the severity of hypernatremia and performed propensity score matching analysis. Results : Among 1146 patients, 353 patients (30.8%) showed hypernatremia. Based on propensity score matching, 290 pairs were included in the analysis. The hypernatremia group had higher rates of in-hospital mortality and 28-day mortality in both overall and matched population (both p<0.001 and p=0.001, respectively). In multivariable analysis of propensity score-matched population, moderate and severe hypernatremia were significantly associated with in-hospital mortality (adjusted odds ratio [OR], 4.58; 95% confidence interval [CI], 2.15-9.75 and adjusted OR, 6.93; 95% CI, 3.46-13.90, respectively) and 28-day mortality (adjusted OR, 3.51; 95% CI, 1.54-7.98 and adjusted OR, 10.60; 95% CI, 5.10-21.90, respectively) compared with the absence of hypernatremia. However, clinical outcomes, including in-hospital mortality and 28-day mortality, were not significantly different between the group without hypernatremia and the group with mild hypernatremia (p=0.720 and p=0.690, respectively). The mortality rates of patients with moderate and severe hypernatremia were significantly higher in both overall and matched population. Interestingly, the mild hypernatremia group of matched population showed the best survival rate. Conclusion : Moderate and severe hypernatremia were associated with poor clinical outcomes in neurocritically ill patients. However, the prognosis of patients with mild hypernatremia was similar with that of patients without hypernatremia. Therefore, mild hypernatremia may be allowed during treatment of intracranial hypertension using hyperosmolar therapy.