• Title/Summary/Keyword: statistical evidence

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Extraction of the Talus Distribution Potential Area Using the Spatial Statistical Techniques - Focusing on the Weight of Evidence Model - (공간통계기법을 이용한 애추 분포 가능지역 추출 - Weight of evidence 기법을 중심으로 -)

  • Yu, Jaejin;JANG, Dong-Ho
    • Journal of The Geomorphological Association of Korea
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    • v.21 no.4
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    • pp.133-147
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    • 2014
  • Reducing the range of target landform, is required to save the time and cost before real field survey in the case of inaccessible landform such as talus. In this study, Weight of Evidence modeling, which is a Target-driven spatial analysis statistics methods, has been applied to reduce the field survey range of target landform. In order to apply the Weight of Evidence analysis, a likelihood ratio was calculated on the basis of the result of correlation analysis between geomorphic factors and GIS information after selection of geomorphic factors regarding talus. A best combination, which has the biggest possibility for Talus Potential Index, was found by using SRC and AUC methods after calculating the number of cases for each thematic maps. This combination which includes aspect, geology, slope, land-cover, soil depth and soil drainage factors, showed quite high accuracy by 74.47% indicating the ratio of real existent talus to potential talus distribution.

The Review on the Evidence-Based Study of Acupuncture - Systematic review and Meta-analysis - (침(鍼)의 근거중심적(根據中心的) 연구동향(硏究動向)에 관(關)한 고찰(考察) - Systematic review & Meta-analysis를 중심으로 -)

  • Back, Yong-Hyeon;Park, Dong-Seok;Kang, Sung-Keel
    • Journal of Acupuncture Research
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    • v.19 no.3
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    • pp.138-155
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    • 2002
  • Objective : The purpose of this study is to work on the problems and on the direction of the study regarding the evidence-based study of Acupuncture. Methods : We reviewed the PubMed electronic database. Eight articles of systematic review without meta-analysis and six articles without meta-analysis were selected. Results : In the study of eight articles of systematic review without meta-analysis, there were two articles on effectiveness of acupuncture and one on non-effectiveness of acupuncture. Four articles were about the changes according to the quality of randomized controlled trials. Also, one article was about the side-effect of acupuncture. In the study of six articles of systematic review with meta-analysis, there were two articles on Odds Ratio, two on Relative Risk, one on number-needed-to-treat, and two on 18 predefined methodological criteria. Conclusion : As the quality of RCTs was high, positive response decreased and as the quality of RCTs was low, positive response increased. For the study of evidence-based acupuncture, it is necessary that we conduct research on well-planned placebo acupuncture, large sample size, statistical method, method of searching and assessing literature and method of meta-analysis.

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Risk Characteristic on Fat-tails of Return Distribution: An Evidence of the Korean Stock Market

  • Eom, Cheoljun
    • Asia-Pacific Journal of Business
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    • v.11 no.4
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    • pp.37-48
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    • 2020
  • Purpose - This study empirically investigates whether the risk property included in fat-tails of return distributions is systematic or unsystematic based on the devised statistical methods. Design/methodology/approach - This study devised empirical designs based on two traditional methods: principal component analysis (PCA) and the testing method of portfolio diversification effect. The fatness of the tails in return distributions is quantitatively measured by statistical probability. Findings - According to the results, the risk property in the fat-tails of return distributions has the economic meanings of eigenvalues having a value greater than 1 through PCA, and also systematic risk that cannot be removed through portfolio diversification. In other words, the fat-tails of return distributions have the properties of the common factors, which may explain the changes of stock returns. Meanwhile, the fatness of the tails in the portfolio return distributions shows the asymmetric relationship of common factors on the tails of return distributions. The negative tail in the portfolio return distribution has a much closer relation with the property of common factors, compared to the positive tail. Research implications or Originality - This empirical evidence may complement the existing studies related to tail risk which is utilized in pricing models as a common factor.

Statistical Data Extraction and Validation from Graph for Data Integration and Meta-analysis (데이터통합과 메타분석을 위한 그래프 통계량 추출과 검증)

  • Sung Ryul Shim;Yo Hwan Lim;Myunghee Hong;Gyuseon Song;Hyun Wook Han
    • The Journal of Bigdata
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    • v.6 no.2
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    • pp.61-70
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    • 2021
  • The objective of this study was to describe specific approaches for data extraction from graph when statistical information is not directly reported in some articles, enabling data intergration and meta-analysis for quantitative data synthesis. Particularly, meta-analysis is an important analysis tool that allows the right decision making for evidence-based medicine by systematically and objectively selects target literature, quantifies the results of individual studies, and provides the overall effect size. For data integration and meta-analysis, we investigated the strength points about the introduction and application of Adobe Acrobet Reader and Python-based Jupiter Lab software, a computer tool that extracts accurate statistical figures from graphs. We used as an example data that was statistically verified throught an previous studies and the original data could be obtained from ClinicalTrials.gov. As a result of meta-analysis of the original data and the extraction values of each computer software, there was no statistically significant difference between the extraction methods. In addition, the intra-rater reliability of between researchers was confirmed and the consistency was high. Therefore, In terms of maintaining the integrity of statistical information, measurement using a computational tool is recommended rather than the classically used methods.

Statistical Bias and Inflated Variance in the Genehunter Nonparametric Linkage Test Statistic

  • Song, Hae-Hiang;Choi, Eun-Kyeong
    • Communications for Statistical Applications and Methods
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    • v.16 no.2
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    • pp.373-381
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    • 2009
  • Evidence of linkage is expressed as a decreasing trend of the squared trait difference of two siblings with increasing identical by descent scores. In contrast to successes in the application of a parametric approach of Haseman-Elston regression, notably low powers are demonstrated in the nonparametric linkage analysis methods for complex traits and diseases with sib-pairs data. We report that the Genehunter nonparametric linkage statistic is biased and furthermore the variance formula that they used is an inflated one, and this is one reason for a low performance. Thus, we propose bias-corrected nonparametric linkage statistics. Simulation studies comparing our proposed nonparametric test statistics versus the existing test statistics suggest that the bias-corrected new nonparametric test statistics are more powerful and attains efficiencies close to that of Haseman-Elston regression.

How to identify fake images? : Multiscale methods vs. Sherlock Holmes

  • Park, Minsu;Park, Minjeong;Kim, Donghoh;Lee, Hajeong;Oh, Hee-Seok
    • Communications for Statistical Applications and Methods
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    • v.28 no.6
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    • pp.583-594
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    • 2021
  • In this paper, we propose wavelet-based procedures to identify the difference between images, including portraits and handwriting. The proposed methods are based on a novel combination of multiscale methods with a regularization technique. The multiscale method extracts the local characteristics of an image, and the distinct features are obtained through the regularized regression of the local characteristics. The regularized regression approach copes with the high-dimensional problem to build the relation between the local characteristics. Lytle and Yang (2006) introduced the detection method of forged handwriting via wavelets and summary statistics. We expand the scope of their method to the general image and significantly improve the results. We demonstrate the promising empirical evidence of the proposed method through various experiments.

The Effects of Message Framing and Evidence Type on Obesity Prevention for Chinese Adolescents (메시지 프레이밍과 증거 유형에 따른 중국 청소년 비만예방 메시지 효과)

  • Shu, Xiaoshuang;Choi, Youjin
    • The Journal of the Korea Contents Association
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    • v.18 no.3
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    • pp.626-635
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    • 2018
  • To develop prevention messages for increasingly severe adolescent obesity in China. this study tested interaction effects between obesity involvement and message framing, and between obesity involvement and evidence types on obesity prevention attitudes and behavioral intentions. Message framing types are categorized with a gain frame and a loss frame. Evidence types are classified into narratives based on personal experiences and statistics based on objective numerical proofs. Three hundred sixty eight Chinese adolescents participated in the study. Results found that involvement, framing, and evidence types had significant effects on attitudes and behavioral intentions to obesity prevention. Adolescents highly involved in obesity were more likely to show positive attitudes and behavioral intentions when exposed to loss framing and statistical evidence. Those with low involvement showed positive attitudes and behavioral intentions after exposed to gain framing and narratives. Thus, we suggest that loss frames with numerical data should be developed to persuade adolescents with high involvement, and gain frames with narratives should be developed for those with low involvement.

A Study on the Development of Index for Food Safety Status based on the Statistical Data (식품안전수준에 대한 지수 개발 연구)

  • Yang, Sung-Bum
    • Korean Journal of Organic Agriculture
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    • v.30 no.1
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    • pp.21-35
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    • 2022
  • Measuring the food safety has been focused only on the psychological consumers' recognition of food safety. The actual measurement tool should consist of the evidence-based statistical data to assess the level of national food safety in scientific perspectives. This paper described the development of a concept to measure the food safety of the food chain based on OECD PSR framework. This paper discusses the elaboration of a set of 8 food safety related data issued as statistical data, and which were same weighted. These food safety statistical data (FSDs) were derived as the basis of measuring the variation of food safety during 2013-2019. The values of the primary production indicator (PPI), the processing and manufacturing indicator (PMI), and the distribution and consumption indicator (DCI) are 0.558-0.859, 0.533-0.691, and 0.979-0.982, respectively. The food safety status (FSS) derived from the safety indicator values of each of the three stages is 0.700-0.810. In order to increase the level of food safety, it is necessary to pay attention to PMI and PPI management. In the future, continuously calculating the level of food safety, managing it like the level of psychological safety, and further expanding it to the level of food safety between countries will help establish policies to improve the level of food safety in Korea.

A pooled Bayes test of independence using restricted pooling model for contingency tables from small areas

  • Jo, Aejeong;Kim, Dal Ho
    • Communications for Statistical Applications and Methods
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    • v.29 no.5
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    • pp.547-559
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    • 2022
  • For a chi-squared test, which is a statistical method used to test the independence of a contingency table of two factors, the expected frequency of each cell must be greater than 5. The percentage of cells with an expected frequency below 5 must be less than 20% of all cells. However, there are many cases in which the regional expected frequency is below 5 in general small area studies. Even in large-scale surveys, it is difficult to forecast the expected frequency to be greater than 5 when there is small area estimation with subgroup analysis. Another statistical method to test independence is to use the Bayes factor, but since there is a high ratio of data dependency due to the nature of the Bayesian approach, the low expected frequency tends to decrease the precision of the test results. To overcome these limitations, we will borrow information from areas with similar characteristics and pool the data statistically to propose a pooled Bayes test of independence in target areas. Jo et al. (2021) suggested hierarchical Bayesian pooling models for small area estimation of categorical data, and we will introduce the pooled Bayes factors calculated by expanding their restricted pooling model. We applied the pooled Bayes factors using bone mineral density and body mass index data from the Third National Health and Nutrition Examination Survey conducted in the United States and compared them with chi-squared tests often used in tests of independence.

A Case Study on Statistic-Based Policy: Use of the Housing Purchase Price Indices (통계기반 정책사례 연구: 주택가격지수 통계의 구축, 개선, 활용을 중심으로)

  • Park, Jin-Woo
    • The Korean Journal of Applied Statistics
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    • v.22 no.3
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    • pp.635-651
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    • 2009
  • Democratization and advancement of a society requires the Government's commitment to evidence-based policy. Though statistic is known as one of the best available evidence, there has been only a few case studies to tell real stories about using statistics for policy making. The object of this study is to suggest some real stories about using the Housing Purchase Price Survey for some property policies. By reviewing the origin and development of the survey, we evaluate the design and analysis strategies adopted in the survey. In addition, we describe how the Housing Purchase Price Indices have been used by the Government for some property policies.