• Journal of the Korean Data and Information Science Society
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• v.7 no.2
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• pp.235-245
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• 1996

In this paper, we studied about several methods of testing hypothesis of correlation, specially Approximate method, Empirical method and Bootstrap method. The Approximate method is based on the Fisher's Z-transformation and the Empirical and Bootstrap methods approximate the distribution of the sample correlation coefficient by Monte Carlo simulation and Bootstrap technique, respectively. In order to compare how good these tests are, we computed powers under various alternatives. Consequently, we see that the Approximate test performs very well even if in small sample and all tests have almost the same power in large sample.

• Journal of the Korean Data and Information Science Society
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• v.19 no.4
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• pp.1101-1110
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• 2008

The present paper investigates about the formation of the logical thinking and the intuitive thinking in mathematical concepts with reference to secondary talented students (students aged 16$\sim$17 years). As a main result, we conclude that their preference between the logical and the intuitive thinking does not related to the distinction of the school level and sex, while their consistence between them relates.

• Journal of the Korean Data and Information Science Society
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• v.25 no.5
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• pp.1039-1055
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• 2014

The distribution of a test statistic under a null hypothesis depends on the unknown distribution of the data and thus is unknown as well. Conditional tests replace the unknown null distribution by the conditional null distribution, that is, the distribution of the test statistic given the observed data. This approach is known as permutation tests and was developed by Fisher (Fisher, 1935). Theoretical framework for permutation tests was given by Strasser and Weber(1999). The coin package developed by Hothon et al. (2006, 2008) implements a unified approach for conditional inference via the generic independence test. Because convenient functions for the most prominent problems are available, users will not have to use the extremely flexible procedure. In this article we briefly review the underlying theory from Strasser and Weber (1999) and explain how to transform the data to perform the generic function independence test. Finally it was illustrated with a few real data sets.

• Journal of dental hygiene science
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• v.6 no.1
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• pp.19-22
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• 2006

To prepare basic data for oral health promotion of high school students through the survey of the recognition of oral health, a questionnaire survey was conducted for 369 students. Statistical analysis was conducted using the SPSS 11.5 with $x^2$-test, fisher's exact test, t-test. The obtained results were as follows 1. The average of the high school student's DMF rate, DMFT index and SiC Index was 87.53%, 3.36, 6.50. 2. The average of the high school student's oral health knowledge was more than 3, 70% of highschool did right toothbrushing. But toothbrushing frequency of student of more than 60% was less than 2 a day. 3. In SiC Index, Only 30% of high school students received oral health education and 80% of them recognized oral health manpower's education needs.

• Journal of the Korean Data Analysis Society
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• v.20 no.6
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• pp.2907-2915
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• 2018

Journal of the Korean Data Analysis Society founded in 1998 has played the role of a major application journal. In this study, we checked the objective of this journal by checking the abstracts for 10 years. Abstract data was crawled from the online journal site (kdas.jems.or.kr) and analyzed by topic model. As a result, we found 18 topics from 2680 abstracts that had several contents, for example, nursing, marketing, economics, regression, factor analysis, data mining and statistical inferences. Topic1 (regression) is most frequent with 460 documents and we found the usefulness of regression in the applied science area. We confirmed the significant 10 association rules using by Fisher's exact test. Also, for exploring the trend of topics, we conducted the topic analysis for two periods which are 2006-2011 period and 2012-2016 period. We found that the control study was more frequent than survey study over time and regression and factor analysis were frequent regardless of time.

• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.447-451
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• 2019

This study were to investigate the scratches and replacement cycles of eyeglasses according to personal characteristics in daily life. The subjects were 58 people who voluntarily participated in this study. The replacement cycle of eyeglasses according to the contact of eyelashes with eyeglasses, type and the number of eyeglasses wiped on a day were analyzed. The statistical analysis were performed by X² test and Fisher's exact test. The average replacement cycle of the eyeglasses were longer females than males. The eyeglasses replacement cycle were significantly shorter when the eyelashes contacted the eyeglasses and when the eyeglasses were wiped using a tissue or clothes other than the eyeglasses towel. The coating film of the eyeglasses may be damaged by the convergence effect such as eyelashes or minor carelessness in daily life, and this study will continue to follow up on this result.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.1
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• pp.29-37
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• 2019

The purpose of this study was to investigate the characteristics of intrusion in primary dentition and to evaluate factors influencing complications of primary and permanent dentition during long-term follow-up period. 61 patients (84 teeth) were selected in this study. Medical records of 61 patients were reviewed and age, gender, cause of injury, site of injury, severity of traumatic injury, other injuries associated with trauma, treatment method, and complications of primary and permanent dentition were examined. Collected data were statistically evaluated using Chi-square test and Fisher's exact test. Intrusion in primary anterior teeth was predominant in boys over girls and fall was the most common cause of trauma. It was most common at home and occurred most in the primary maxillary central incisors. Severity had an effect on the incidence of sequelae in permanent successors (p = 0.014). The incidence of complications was significantly lower in patients with soft tissue injuries than in patients with other periodontal injuries (p = 0.000).

• Journal of Digital Convergence
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• v.19 no.6
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• pp.419-427
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• 2021

The purpose of this study is to identify the recognition and utilization of health information by acquisition channels for preliminary and elderly people. For the survey data of 200 people aged 55 to 64 and 200 seniors aged 65 or older, the chi-square test and Fisher's precision test were performed using MINITAB17. Although the two age groups were similar in obtaining health information through health professionals, preliminary elderly were more likely to obtain health information through mass media and Internet sites. In particular, the collection of health information through internet sites was more than four times higher than that of the elderly. While the preliminary people focused on searching the information on the health care and prevention, older people explored comprehensive information on health, including disease prevention and treatment, through each channel. Both groups showed positive recognition about the acquired health information. The results of this study confirmed that all channels, including internet sites, can be usefully used in the delivery of health-related information to the elderly in the future. In addition, it is suggested to consider age characteristics and health information utilized by each channel in the development of various contents for the improvement of self-health management of the elderly.

• Journal of the Korean Society of Radiology
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• v.81 no.2
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• pp.379-394
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• 2020

Purpose To design a scoring system to predict malignancy of additional MRI-detected lesions in breast cancer patients. Materials and Methods Eighty-six lesions (64 benign and 22 malignant) detected on preoperative MRI of 68 breast cancer patients were retrospectively included. The clinico-radiologic features were correlated with the histopathologic results using the Student's t-test, Fisher's exact test, and logistic regression analysis. The scoring system was designed based on the significant predictive features of malignancy, and its diagnostic performance was compared with that of the Breast Imaging-Reporting and Data System (BI-RADS) category. Results Lesion size ≥ 8 mm (p < 0.001), location in the same quadrant as the primary cancer (p = 0.005), delayed plateau kinetics (p = 0.010), T2 isointense (p = 0.034) and hypointense (p = 0.024) signals, and irregular mass shape (p = 0.028) were associated with malignancy. In comparison with the BI-RADS category, the scoring system based on these features with suspicious non-mass internal enhancement increased the diagnostic performance (area under the receiver operating characteristic curve: 0.918 vs. 0.727) and detected three false-negative cases. With this scoring system, 22 second-look ultrasound examinations (22/66, 33.3%) could have been avoided. Conclusion The scoring system based on the lesion size, location relative to the primary cancer, delayed kinetic features, T2 signal intensity, mass shape, and non-mass internal enhancement can provide a more accurate approach to evaluate MRI-detected lesions in breast cancer patients.

• Tuberculosis and Respiratory Diseases
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• v.50 no.6
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• pp.686-692
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• 2001

Background : Outbreaks of multidrug-resistant tuberculosis(MDR-TB) are caused by the low rate of treatment response due to limitation in number of available drugs and high rates of adverse drug side-effects. This study analysed the risk factors for MDR-TB patients, who did not respond to treatment, with an aim to improve the rate of treatment response. Methods : Retrospective study of 111 MDR-TB patients at National Mokpo Tuberculosis Hospital from Jan. 1996 to Dec. 1998 was made. The patients were separated into two groups ; group I comprised of patients who were treated successfully and group II comprised of those were not treated successfully. In order to analyze the risk factors for treatment failure, differences between the two groups were compared and the confidence limit regarding the results were tested using an independent t-test. chi-square test and a Fisher's exact test. Results : The treatment failure rate of MDR-TB patients was 32% (36 patients), and treatment success rate 68%(75 patients). This study found no significant difference between two groups in terms of age, sex, family history, extent of the disease on the chest X-ray, the number of sensitive drugs in the treatment regimen, and the number of sensitive bactericidal drugs in the treatment regimen (p>0.05). However, a past history of pulmonary tuberculosis, cavitary lesions on the chest X-ray, the number of treatments, the number of resistant drugs and the number of drugs used showed a significant difference(p<0.05). Conclusion : The rate of treatment failure in MDR-TB was increased by a past history of pulmonary tuberculosis, cavitary lesions on the chest X-ray, the number of treatments, the number of resistant drugs and the number of drugs used. For improving the treatment response of MDR-TB, every effort should be made to reduce the drug resistance caused by failure of the first treatment.