• The Korean Journal of Applied Statistics
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• v.22 no.6
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• pp.1249-1263
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• 2009

The power function in sample size determination has to be characterized by an appropriate statistical test for the hypothesis of interest. Nonparametric tests are suitable in the analysis of ordinal data or frequency data with ordered categories which appear frequently in the biomedical research literature. In this paper, we study sample size calculation methods for the Wilcoxon-Mann-Whitney test for one- and two-dimensional ordinal outcomes. While the sample size formula for the univariate outcome which is based on the variances of the test statistic under both null and alternative hypothesis perform well, this formula requires additional information on probability estimates that appear in the variance of the test statistic under alternative hypothesis, and the values of these probabilities are generally unknown. We study the advantages and disadvantages of different sample size formulas with simulations. Sample sizes are calculated for the two-dimensional ordinal outcomes of efficacy and safety, for which bivariate Wilcoxon-Mann-Whitney test is appropriate than the multivariate parametric test.

• The Korean Journal of Applied Statistics
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• v.21 no.6
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• pp.933-945
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• 2008

The genetic association test on age of onset trait aims to detect the putative gene by means of linear rank tests for a significant trend of onset distributions with genotypes. However, due to the selective sampling of recruiting subjects with ages less than a pre-specified limit, the genotype groups are subject to substantially different censored distributions and thus this is one reason for the low efficiencies in the linear rank tests. In testing the equality of two survival distributions, log-rank statistic is preferred to the Wilcoxon statistic, when censored observations are nonignorable. Therefore, for more then two groups, we propose a generalized log-rank test for trend as a genetic association test. Monte Carlo studies are conducted to investigate the performances of the test statistics examined in this paper.

• Journal of the Korean Data and Information Science Society
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• v.24 no.6
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• pp.1241-1251
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• 2013

The purpose of this study was to investigate and compare the effects of aerobic and complex exercise on body composition and blood lipids in the middle-aged women. Sixteen women whose ages ranged in 40 to 50 years were included in the sample of the study. The sample was divided into two groups: (a) aerobic exercise group (n = 8) and (b) combined exercise training group (n = 8). The aerobic exercise program consisted of bicycle ergometer, stepper, and treadmill, whereas; the combined exercise program was designed to improve muscular strength and aerobic capacity. Both programs took place 4 times a week for 12 weeks with the gradual increase of intensity (HRmax 60% 75% and 1 RM 60% 80%). Data were analyzed by nonparametric methods for pre-post within group mean differences (Wilcoxon signed rank test) and for between group mean differences (Wilcoxon rank sum test). Results indicated that there were statistically significant differences in BMI, body fat mass, and triglyceride within the sample of combined exercise; whereas, no significance existed in any variables within the aerobic exercise group. Results also revealed that statistical significance did exist in body fat mass between the combined and aerobic exercise group. These results implies that the combined exercise may be superior to aerobic only excercise for the body composition and blood lipid of the middle-aged women.

• The Korean Journal of Applied Statistics
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• v.14 no.1
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• pp.149-160
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• 2001

In this paper we employ two-sample location tests such as Wilcoxon test and T test for detecting edges in noisy images. For this, we compute a test statistic on pixel gray levels obtained using an edge-height parameter and compare it with a threshold determined by a significance level. Experimental results applied to sample images are given and performances of these tests in terms of the objective measure are compared.

• Journal of the Korean Data and Information Science Society
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• v.27 no.2
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• pp.337-351
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• 2016

There exist many real situations that statistical decision problems are classified into more than two categories. In these cases, the concordance statistics by the pair approach are mostly used. However, the expression of the classification of categories are ambiguous. Recently, the standardized evaluation data and re-expressed concordance statistics are defined and could be explained their meanings. They have still some non-specific problems for standard criteria of the statistics. Since these can be considered between result and truth categories additionally, two alternative concordance statistics might be proposed in this paper. Some advantages are founded that the proposed statistics could be discriminated all possible cases for two randomly selected categories. Moreover since the proposed statistics are represented with indicator functions, these could be transformed non-parametrically, so that these concordances are used for hypothesis testing.

• Journal of Korea Port Economic Association
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• v.26 no.3
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• pp.18-41
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• 2010

The purpose of this paper is to show the empirical measurement way for predicting the seaport efficiency by using Super SBM(Slack-based Measure) with Wilcoxson signed-rank test under CRS(constant returns to scale) condition for 20 Korean ports during 11 years(1997-2007) for 3 inputs(port investment amount, birthing capacity, and cargo handling capacity) and 5 outputs(Export and Import Quantity, Number of Ship Calls, Port Revenue, Customer Satisfaction Point for Port Service and Container Cargo Throughput). The main empirical results of this paper are as follows. First, Super SBM model has well reflected the real data according to the Wilcoxon signed rank test, because p values have exceeded the significance level. Second,Super-SBM has shown about 87% of predicting ratio for the ports efficiency and the optimal size of investment in domestic seaport. The policy implication to the Korean seaports and planner is that Korean seaports should introduce the new methods like Super-SBM method with Wilcoxon signed rank test for predicting the efficiency of port performance and the optimal size of investment as indicated by Panayides et al.(2009, pp.203-204).

• Journal of the Korean Data and Information Science Society
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• v.21 no.4
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• pp.747-756
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• 2010

With the recent recession, studies on the economy are actively being conducted throughout the industry. Based on the Small Business data registered in the Credit Guarantee Fund, we estimated the survival probability in the context of the survival analysis. We also analyzed the survival time for the construction and the other industries which are distinguished depending on the types of business and assets in the Small Business. The survival probability was estimated by using the life-table and the difference between the survival probabilities for the different types of business was described via the method of the Log-rank test and the Wilcoxon test. We found that the small business with over one billion asset has the highest survival probability and that with less than 1000 million asset showed the similar survival probability. In terms of types of business Wholesale and Retail trade industry and Services were relatively high in the survival probability than Light, Heavy, and the construction industries. Especially the construction industry showed the lowest survival probability. Most of the Small Business tend to increase in the hazard rate over time.

• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.235-242
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• 2019

The present paper aims to examine how prospective teachers' experience of creating UCC materials affects their teaching expertise and creativity. The group of subjects consists of a group of 19 students majoring in Japanese under the teacher certificate curriculum at N University located in Cheonan. The collected data was analyzed using a set of statistical methods including frequency analysis, descriptive statistics, correlation analysis, Wilcoxon Signed Rank Test using SPSS WIN 21.0. It was found that there was a positive correlation between their UCC experiences and their teaching subject expertise/creativity. It was also found that the former exerted a statistically significant effect on the latter. The results of the current research might suggest that teachers' teaching methods in the field are very important. It is hopeful that innovative teaching methods and activities will be introduced and expanded in the filed to produce more effective education.The Korea Convergence Society.

• Journal of the Korean Data and Information Science Society
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• v.23 no.2
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• pp.257-269
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• 2012

Global crisis expedites the change in the environment of industry and puts small size enterprises in danger of mass bankruptcy. Because of this, domestic small size enterprises is an urgent need of restructuring. Based on the small business data registered in the Credit Guarantee Fund, we estimated the survival probability in the context of the survival analysis. We also analyzed the survival time which are distinguished depending on the types of business in the small business. Financial variables were also conducted using COX regression analysis of small businesses by types of business. In terms of types of business wholesale and retail trade industry and services were relatively high in the survival probability than light, heavy, and the construction industries. Especially the construction industry showed the lowest survival probability. In addition, we found that construction industry, the bigger BIS (bank of international settlements capital ratio) and current ratio are, the smaller default-rate is. But the bigger borrowing bond is, the bigger default-rate is. In the light industry, the bigger BIS and ROA (return on assets) are, the smaller a default-rate is. In the wholesale and retail trade industry, the bigger bis and current ratio are, the smaller a default-rate is. In the heavy industry, the bigger BIS, ROA, current ratio are, the smaller default-rate is. Finally, in the services industry, the bigger current ratio is, the smaller a default-rate is.

• The Journal of Korean Society for Radiation Therapy
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• v.16 no.1
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• pp.73-77
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• 2004

Purpose of the radio-therapy is maximize the radiation dose to the tumor while minimizing the dose to the critical organ. Carcinoma of the uterine cervix treatment are external irradiation or an interstitial brachtheraphy make use of isotope. Brachytherapy is a method of radiotherapy in advantage to achieve better local control with minimum radiation toxicity in comparison with external irradiation because radiation dose is distributed according to the inverse square low of gamma-ray emitted from the implanted sources. Authors make use of the patients data which 192Ir gives medical treatment intrcavity. Intracavitary radiation of the uterine cervix cancer, critical organ take $20\%$ below than exposure dose of A point in the ICRU report. None the less of the advice, Radiation proctitis and radiation cystitis are frequent and problematic early complications in patients treated with radiation for the uterine cervix cancer. In brachytherapy of uterine cervical cancer using a high dose rate remote afterloading system, it is of prime importance to deliver a accurate dose in each fractionated treatment by minimizing the difference between the pre-treatment planned and post-treatment calculated doses. Use of packing to reduce late complications intracavitary radiation of the uterine cervix cancer. Bladder and rectum changes exposure dose rate by radiotherphy make use of packing.