• Title/Summary/Keyword: Wilcoxon

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Asymptotic Relative Efficiency for New Score Functions in Rank Regression Models (순위회귀모형의 새로운 스코어 함수의 효율성 연구)

  • 최영훈
    • The Korean Journal of Applied Statistics
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    • v.17 no.2
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    • pp.269-280
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    • 2004
  • We explore the selection of r and s that provides improvement over the Wilcoxon scores under the asymmetric distributions we encounter in practice. We select 0 〈 r 〈 1, s 〉 1 for right-skewed distribution and r 〉 1,0 〈 s 〈 1 for left-skewed distributions from the perspective plots. We also study the association between the desirable r and s and the test statistic for skewness.

Effect of Artificial Aeration System on Water Quality of Yeoncho Lake (연초호의 인공 순환 장치 운영에 의한 수질 개선 효과 분석)

  • Seo, Dong-Il;Hwang, Hyun-Dong;Lee, Eun-Hyoung;Heo, Woo-Myung
    • Journal of Korean Society of Water and Wastewater
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    • v.18 no.3
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    • pp.357-365
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    • 2004
  • Effect of artificial circulation on amelioration of water quality in Yeoncho Lake was analyzed using summer data between 1991-2002. Two sites, intake tower area where aeration systems are concentrated in and near the inlet of reservoir were selected for comparison in this study. Summer averages between may and september Showed that aeration system might be beneficial in the improvement of water quality of BOD5, COD, and TN while Chl-a concentration and transparency did show opposite pattems. Wilcoxon's singed rank test for matched pair indicated slight increase of BOD5 and COD concentrations in the vicinity of intake tower while other variables did not show any significant differences from data of inlet of reservoir. During the study, it was found that the following subjects need to be investigated for more detailed analysis. 1) Dynamic pollutant loading from outside and inside the lake, 2) Biological, Chemical and Physical lake data when aeration systems are in and not in operation and 3) Radius of influence of aeration system.

Efficient Edge Detection in Noisy Images using Robust Rank-Order Test (잡음영상에서 로버스트 순위-순서 검정을 이용한 효과적인 에지검출)

  • Lim, Dong-Hoon
    • The Korean Journal of Applied Statistics
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    • v.20 no.1
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    • pp.147-157
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    • 2007
  • Edge detection has been widely used in computer vision and image processing. We describe a new edge detector based on the robust rank-order test which is a useful alternative to Wilcoxon test. Our method is based on detecting pixel intensity changes between two neighborhoods with a $r{\times}r$ window using an edge-height model to perform effectively on noisy images. Some experiments of our robust rank-order detector with several existing edge detectors are carried out on both synthetic images and real images with and without noise.

Effects of an Empowerment Program on Nicotine Dependency, Temptation, Self-esteem, Depression in Adolescents Who Smoke (역량강화프로그램이 흡연청소년의 니코틴의존도, 흡연유혹 및 자아존중감, 우울에 미치는 효과)

  • Park, Nam-Hee
    • Child Health Nursing Research
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    • v.18 no.1
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    • pp.1-8
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    • 2012
  • Purpose: The purpose of this study was to identify the effects of an empowerment program on nicotine dependency, temptation, self-esteem, and depression for adolescents who smoke. Methods: The study design was a quasi-experimental study with a nonequivalent control group, pre-post design. The participants were 49 adolescents who smoked. Twenty-six adolescents were assigned to the experimental group and 23 to the control group. The intervention was conducted twice a week for 6 weeks. Chi-square test, t-test, paired-test, Wilcoxon rank sum test and Wilcoxon signed rank test were used to analyze the data. Results: After program, scores for self-esteem (t=5.560, p=.014), were significantly higher and scores for depression (t=-2.111, p=.040) were significantly lower for adolescents in the experimental group compared to adolescents in the control group. Conclusion: The finding indicate that the empowerment group training program was effective in improving self-esteem, and decreasing depression and could be considered as a positive program for smoking cessation for adolescents who smoke.

Effects of Foot Reflexzone Massage on State-Anxiety and Discomfort in Ovari an Cancer Patients Receiving Chemotherapy (발반사 마사지가 항암화학요법을 받는 난소암 환자의 불안과 불편감에 미치는 효과)

  • Hwang, Kyung-Hye;Choi, Euy-Soon;Yoo, Yang-Sook
    • Women's Health Nursing
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    • v.11 no.3
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    • pp.209-217
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    • 2005
  • Purpose: This study was conducted to investigate the effects of foot reflexzone massage on state - anxiety and discomfort of ovarian cancer patients receiving chemotherapy. Method: A quasi experimental design with a non equivalent control group and non synchronized design was used. The experiment was conducted from October 1, 2003 to September 30, 2004. The subjects consisted of 40 patients admitted to C University Hospital. Twenty subjects were assigned to the experimental group and received foot reflexzone massage everyday for 3 days. The other 20 subjects were in the control group and received routine care. Foot reflexzone massage was done on both feet of the subjects for 30 minutes for 3 days using standard protocol. The 'State-Anxiety Inventory' developed by Spielberger was used to measure the degree of state-anxiety. Discomfort was assessed using the 'Symptom Distress Scale' of McCorkle and Young. Data was analyzed by a SAS program using t-test, Wilcoxon signed rank sum test and Wilcoxon rank sum test. Results: State-anxiety and discomfort of subjects receiving foot reflexzone massage were significantly lower than those of the control group. Conclusion: These findings indicate that foot reflexzone massage could be an effective nursing intervention for relieving state-anxiety and discomfort in ovarian cancer patients.

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Transforming Pre-service Teachers into Data-Driven Educators: A Developmental Research

  • Huijin SEOK ;Jiwon LEE ;Eunjeong SONG ;Jeongmin LEE
    • Educational Technology International
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    • v.24 no.2
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    • pp.169-202
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    • 2023
  • This study aims to develop instructional design strategies included in educational programs that can effectively improve the educational data literacy of pre-service teachers. We used the design and development model proposed by Richey and Klein and investigated its internal and external validity. Internal validity assessment involved the input of five experts who evaluated the initial instructional strategies. We conducted an educational data literacy education program with 29 pre-service teachers from Korean colleges and graduate schools for external validity. The effectiveness of the program was verified by the Wilcoxon Rank Sum Test, which revealed a meaningful statistical difference between Wilcoxon Rank Sum Test post-scores after the four weeks of online classes. Therefore, this study developed instructional strategies followed by the steps of data-based decision-making: the final instructional strategies encompass 21 strategies, categorized for implementation before, during, and after classes, accompanied by 38 detailed guidelines. This approach bears notable significance as it encapsulates actionable and effective instructional strategies thoughtfully tailored to the unique circumstances and educational setting of the field, as well as the specific characteristics and requirements of the learners.

A Study on the Effects of Art Therapy on the Dementia Elderly (치매노인의 집단미술치료 효과에 관한 연구)

  • Lee, Hyun Sim;Kim, Seong Yong
    • 한국노년학
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    • v.28 no.4
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    • pp.1279-1295
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    • 2008
  • This study was done to find out the effects that group art therapy would have on low rank cognitive functions and the self-esteem of the elderly with dementia. The study subjects were four elderly females with light dementia symptoms who scored lower than 19 points on the MMSE-K(Mini Mental State Examination-Korea) test. They were chosen from the ${\bigcirc}{\bigcirc}$ Senior Welfare Service Center located in Seoul. A total of 15 sessions of a group art therapy were given once a week for 60 minutes from January 15th to April 30th of 2008, the research tools employed were the MMSE-K and the Rosenberg Self-Esteem Scale on which a pre-test and a post-test were given. The results obtained are as follows. First, it was shown that group art therapy is effective to improve the cognitive functions of the elderly with dementia. According to the pre-tests and post -tests based on MMSE-K, the average score improved from 16.75 to 19.75, using Wilcoxon non-parameter statistics, verification resultant p-value which significant difference exhibited as .046, from the pre-tests and post-test, the average score improved in the subordinate areas of Orientation, Registration, Attention and Calculation, language function, understanding and judgment but there was no significant difference, memory recollection improved by a score of 0.70 according to the pre-test and post-test. using Wilcoxon non-parameter statistics, the verification resultant p-value which significant difference exhibited as .043. Second, it appeared with the fact that group art therapy effects the Self-Esteem of the elderly with dementia. From the verifications of a pre-test and post-test on Self-Esteem, the average score improved from 20.75 to 24.25, the effectiveness of the program was given proven by statistically considering the statistical resultant p-value of .048.

Analysis on the Area by Forest Function and the Reflection of Ecosystem Service Concepts in Korea's National Forest Management Plans (최근 국유림경영계획에서 산림기능별 면적구분과 생태계서비스 개념의 반영에 관한 분석)

  • Ko, Kiyeon;Choi, Jaeyong
    • Journal of Korean Society of Forest Science
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    • v.109 no.2
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    • pp.211-222
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    • 2020
  • This study tried to find out whether there is a change over time in the functional classification of forests in relation to human demand for forests. The level in which the concept of ecosystem services has been considered in national forest management plans was also examined. A total of 98 current and previous national forest management plans were available for this study. The composition ratios of the six functions of forests in both the current and previous national forest management plans were surveyed. We used a parametric t-test when the mean values of two (current and previous) groups were normally distributed and used nonparametric Wilcoxon code rank test when the assumption of normality was not met. Timber production forests were shown to follow a normal distribution, while five others, including water regeneration forests, disaster prevention forests, natural environment conservation forests, recreation forests, and living environment conservation forests were not shown to follow a normal distribution. Timber production forests and natural environment forests showed significant changes in the proportion of forest area between previous and current forest management plans. The concept of 'ecosystem services' began to actively appear in the 6th Basic Forest Plan, which started in 2018. However, the level of frequency of the ecosystem services mentioned varied by Regional Forest Services.

A Study on the Model Development and Empirical Application for Predicting the Efficiency and Optimum Size of Investment in Domestic Seaports (국내항만투자의 효율성 및 적정 투자규모 예측을 위한 모형개발 및 실증적 적용에 관한 연구)

  • Park, Ro-Kyung
    • 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).

The Impact of Abdominal Muscle Strengthening Exercises, Back Muscle Stretching and Multi-Training on the Lumbar Flexibility of 20s Adults (복부근력강화운동, 배부근 스트레칭 및 복합운동이 20대 성인의 허리 유연성에 미치는 영향)

  • Hong, Ki-Hoon;An, Ji-Hye;Yoo, Sun-Wook;Yun, Hyun-Joo;Lee, Chun-Yeop;Kim, Hee-Jung
    • The Journal of Korean society of community based occupational therapy
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    • v.3 no.2
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    • pp.57-65
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    • 2013
  • Objective : The purpose of this study was to identify the effect and difference of abdominal muscle strengthening exercise, back muscle stretching and multi-training on the lumbar flexibility of 20s adults. Method : The abdominal muscle strengthening exercise, back muscle stretching and multi-training were conducted 9 times targeting 21 subjects who attended K University from 2013 May 29 to June 14. Sit and Reach Tests were conducted 2 times(before and after exercise program) for flexibility test and measured data were processed with SPSS program WIN 12.0K. By the Wilcoxon signed rank test, the effectiveness of exercises are verified. By the Kruskal-Wallis test and Mann-Whitney test, the difference of effectiveness among the exercise groups are verified. Result : The results of this study were summerized below 1. Before and after exercise, in abdominal muscle strengthening exercise group, back muscle stretching group and multi-training group are showed statistically significant differences(p<.05), 2. There were statistically significant difference in the improvement of the flexibility between each group(p>.05). Conclusion : These data suggests that all of the 3 exercise programs are brought positive influences on the improvement of flexibility, and abdominal muscle strengthening exercises and flexibility multi-training are effective on the flexibility more than, back muscle stretching in 20s adults.

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