• Title, Summary, Keyword: Wilcoxon test

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DISTRIBUTiON-FREE TWO-SAMPLE TEST ON RANKED-SET SAMPLES

  • DONG HEE KIM;YOUNG CHEOL KIM;MYUNG HWA CHO
    • Communications for Statistical Applications and Methods
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    • v.5 no.1
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    • pp.133-144
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    • 1998
  • In this paper, we propose the two-sample test statistic using Wilcoxon signed rank test on ranked-set sampling(RSS) and obtain the asymptotic relative efficiencies(ARE) of the proposed test statistic with respect to Mann-Whitney-Wilcoxon statistic on simple random sampling(SRS), the Mann-Whitney-Wilcoxon statistic on RSS, sign statistic on RSS and Wilcoxon signed rank test on SRS. From the simulation works, we compare the powers of the proposed test statistic, Mann-Whitney-Wilcoxon statistic on RSS, the usual two-sample t statistic, sign statistic on RSS, where the underlying distributions are uniform, normal, double exponential, logistic and Cauchy distributions.

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The Wilcoxon Signed-Rank Fuzzy Test on Rate of Internal Division (내분비를 이용한 윌콕슨 부호-순위 퍼지 검정)

  • Kang, Man Ki;Choi, Seung Bae
    • Journal of the Korean Institute of Intelligent Systems
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    • v.24 no.6
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    • pp.592-596
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    • 2014
  • We shall consider fuzzy hypotheses test for signed-rank Wilcoxon fuzzy test by fuzzy difference on rate of internal division. Fundamental to these discussion are fuzzy number data and Wilcoxon signed-rank fuzzy test of a fuzzy hypothesis $H_{f0}$ which is based upon a fuzzy statistics whose distribution does not depend upon the specified distribution or any parameters.

Development of An Automatic Incident Detection Model Using Wilcoxon Rank Sum Test (Wilcoxon Rank Sum Test 기법을 이용한 자동돌발상황검지 모형 개발)

  • 이상민;이승환
    • Journal of Korean Society of Transportation
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    • v.20 no.6
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    • pp.81-98
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    • 2002
  • 본 연구는 Wilcoxon Rank Sum Test 기법을 이용한 자동 돌발상황 검지 모형을 개발하는 것이다. 본 연구의 수행을 위하여 고속도로에 설치된 루프 차량 검지기(Loop Vehicle Detection System)에서 수집된 점유율 데이터를 사용하였다. 기존의 검지모형은 산정하기가 까다로운 임계치에 의하여 돌발상황을 검지하는 방식이었다. 반면 본 연구 모델은 위치와 시간대 교통 패턴에 관계없이 모형을 일정하게 적용하며, 지속적으로 돌발상황 지점과 상·하류의 교통패턴을 비교 검정 기법인 Wilcoxon Rank Sum Test 기법을 사용하여 돌발상황 검지를 수행하도록 하였다. 연구모형의 검증을 위한 테스트 결과 시간과 위치에 관계없이 정확하고 빠른 검지시간(돌발 상황 발생 후 2∼3분)을 가짐을 알 수 있었다. 또한 기존의 모형인 APID, DES, DELOS모형과 비교검증을 위하여 검지율 및 오보율 테스트를 수행한 결과 향상된 검지 능력(검지율 : 89.01%, 오보율 : 0.97%)을 나타남을 알 수 있었다. 그러나 압축파와 같은 유사 돌발상황이 발생되면 제대로 검지를 하지 못하는 단점을 가지고 있으며 향후 이에 대한 연구가 추가된다면 더욱 신뢰성 있는 검지모형으로 발전할 것이다.

Ranked-Set Sample Wilcoxon Signed Rank Test For Quantiles Under Equal Allocation

  • Kim, Dong Hee;Kim, Hyun Gee
    • Communications for Statistical Applications and Methods
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    • v.10 no.2
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    • pp.535-543
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    • 2003
  • A ranked set sample version of the sign test is proposed for testing hypotheses concerning the quantiles of a population characteristic by Kaur, et. al(2002). In this paper, we proposed the ranked set sample Wilcoxon signed rank test for quantiles under equal allocation. We obtain the asymptotic property and the asymptotic relative efficiencies of the proposed test statistic with respect to Wilcoxon signed rank test of simple random sample for quantiles under equal allocation. We calculate the ARE of test statistics, the proposed test statistic is more efficient than simple random sampling for all quantiles. The relative advantage of ranked set sampling is greatest at the median and tapers off in the tails.

Weighted Least Absolute Error Estimation of Regression Parameters

  • Song, Moon-Sup
    • Journal of the Korean Statistical Society
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    • v.8 no.1
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    • pp.23-36
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    • 1979
  • In the multiple linear regression model a class of weighted least absolute error estimaters, which minimize the sum of weighted absolute residuals, is proposed. It is shown that the weighted least absolute error estimators with Wilcoxon scores are equivalent to the Koul's Wilcoxon type estimator. Therefore, the asymptotic efficiency of the proposed estimator with Wilcoxon scores relative to the least squares estimator is the same as the Pitman efficiency of the Wilcoxon test relative to the Student's t-test. To find the estimates the iterative weighted least squares method suggested by Schlossmacher is applicable.

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Development of Statistical Edge Detector in Noisy Images and Implementation on the Web

  • Lim, Dong-Hoon
    • 한국데이터정보과학회:학술대회논문집
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    • pp.197-201
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    • 2004
  • We describe a new edge detector based on the robust rank-order (RRO) test which is a useful alternative to Wilcoxon test, using $r{\times}r$ window for detecting edges of all possible orientations in noisy images. Some experiments of statistical edge detectors based on the Wilcoxon test and T test with our RRO detector are carried out on synthetic and real images corrupted by both Gaussian and impulse noise. We also implement these edge detectors using Java on the Web.

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Sample size comparison for two independent populations (독립인 두 모집단 설계에서의 표본수 비교)

  • Ko, Hae-Won;Kim, Dong-Jae
    • Journal of the Korean Data and Information Science Society
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    • v.21 no.6
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    • pp.1243-1251
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    • 2010
  • For clinical trials, it is common to compare the placebo and new drug. The method of calculating a sample size for two independent populations are the t-test that is used for parametric methods, and the Wilcoxon rank-sum test that is used in the non-parametric methods. In this paper, we propose a method that is using Kim's (1994) statistic power based on the linear placement statistic, which was proposed by Orban and Wolfe (1982). We also compare the sample size for the proposed method with that for using Wang et al. (2003)'s sample size formula which is based on Wilcoxon rank-sum test, and with that of t-test for parametric methods.

Two Sequential Wilcoxon Tests for Scale Alternatives

  • Mishra, Prafulla-Chandra
    • Journal of the Korean Statistical Society
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    • v.30 no.4
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    • pp.679-691
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    • 2001
  • Two truncated sequential tests are developed for the two-sample scale problem based on the usual Wilcoxon rank-sum statistic for two different dispersion indices - absolute median deviations, when the medians of the two populations X and Y are equal or known and sums of squared mean deviations, when the medians are either unknown or unequal. The first test is briefly called SWAMD test and the second SWSMD test. For the SWAMD test, the percentile points for both the one-sided and two-sided alternatives, (equation omitted) have been found by Wiener approximation and their values computed for a range of values of a and N; analytical expression for the power function has been derived through Wiener process and its performance studied for various sequential designs for exponential distribution. This test has been illustrated by a numerical example. All the results of the SWAMD test, being directly applicable to the SWSMD test, are not dealt with separately Both the tests are compared and their suitable applications indicated.

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A Nonparametric Stratified Test Based on the Jonckheere-Terpstra Trend Statistic (Jonckheere-Terpstra 추세 검정통계량에 근거한 비모수적 층화분석법)

  • Cho, Do-Yeon;Yang, Soo;Song, Hae-Hiang
    • The Korean Journal of Applied Statistics
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    • v.23 no.6
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    • pp.1081-1091
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    • 2010
  • Clinical trials are often carried out as multi-center studies because the patients enrolled for a trial study are very limited in one particular hospital. In these circumstances, the use of an ordinary Jonckheere (1954) and Terpstra (1952) test for testing trend among several independent treatment groups is invalid. We propose a the stratified Jonckheere-Terpstra test based on van Elteren (1960)'s stratified test of Wilcoxon (1945) statistics and an application of our method is demonstrated through example data. A simulation study compares the efficiency of stratified and unstratified Jonckheere-Terpstra trend tests.

Comparison of Edge Detection using Linear Rank Tests in Images (영상에서 선형순위검정법을 이용한 에지검출 비교)

  • Lim Dong-Hoon
    • Journal of the Korea Society of Computer and Information
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    • v.10 no.6
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    • pp.17-26
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    • 2005
  • In this paper we propose three nonparametric tests such as Wilcoxon test, Median test and Van der Waerden test, based on linear rank statistics for detecting edges in images. The methods used herein are based on detecting changes in gray-levels obtained using an edge-height parameter between two sub-regions in a 5$\times$5 window We compare and analysis the performance of three statistical edge detectors in terms of qualitative measures with the edge maps and objective, quantitative measures.

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