• Title, Summary, Keyword: t-검정

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Sample size determination based on placements for non-inferiority trials (비열등성 시험에서 위치 방법에 기초한 표본 수 결정)

  • Kim, Jiyeon;Kim, Dongjae
    • Journal of the Korean Data and Information Science Society
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    • v.24 no.6
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    • pp.1349-1357
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    • 2013
  • In clinical research, sample size determination is one of the most important things. There are parametric method using t-test and non-parametric method suggested by Kim and Kim (2007) based on Wilcoxon's rank sum test for determining sample size in non-inferiority trials. In this paper, we propose sample size calculation method based on placements method suggested by Orban and Wolfe (1982) and using the power calculated by Kim (1994) in non-inferiority trials. We also compare proposed sample size with that using Kim and Kim (2007)'s formula and that of t-test for parametric methods. As the result, sample size calculated by proposed method based on placements is the smallest. Therefore, proposed method based on placements is better than parametric methods in case that it's hard to assume specific distribution function for population and also more efficient in terms of time and cost than method based on Wilcoxon's rank sum test.

The Effects on Aromatherapy and Foot Reflex Massage on the Cognition, Anxiety, Aggressive Behavior and Wandering Behavior of Elderly with Dementia (향요법 발반사 마사지가 치매노인의 인지, 불안, 공격행동 및 배회행동에 미치는 효과)

  • Lee, Sun-Young;Lee, Jeong-Sook
    • Journal of Digital Convergence
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    • v.11 no.12
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    • pp.495-505
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    • 2013
  • This study aims to evaluate the effects of aromatherapy and a foot reflex massage program on the cognition, anxiety, aggressive behavior, and wandering behavior of elderly with dementia. The research design was a non-equivalent control group, quasi-experimental study where 43 subjects were divided into two groups. Aromatherapy and foot reflex massage was administered to the experimental group (N=21), and no treatment was administered to the control group (N=22). The data was analyzed using the ${\chi}^2$-test, t-test, while the repeated measures of ANOVA were utilized with the SPSS/Win 18.0 program. The experimental group did not show significant differences in cognitive function; however, it showed significant differences in anxiety, aggressive behavior, and wandering behavior in relation to the control group. Thus this research suggests aromatherapy and a foot reflex massage program as nursing intervention to improve the quality of life of elderly with dementia.

A Robust Test for Location Parameters in Multivariate Data (다변량 자료에서 위치모수에 대한 로버스트 검정)

  • So, Sun-Ha;Lee, Dong-Hee;Jung, Byoung-Cheo
    • The Korean Journal of Applied Statistics
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    • v.22 no.6
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    • pp.1355-1364
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    • 2009
  • This work propose a robust test for location parameters in multivariate data based on MVE and MCD with the affine equivariance and the high-breakdown properties. We consider the hypothesis testing satisfying high efficiency and high test power simultaneously to bring in the one-step reweighting procedure upon high-breakdown estimators, which generally suffer from the low efficiency and, as a result, usually used only in the exploratory analysis. Monte Carlo study shows that the suggested method retains nominal significance levels and higher testing power without regard to various population distributions than a Hotelling's $T^2$ test. In an example, a data set containing known outliers does not make an influence toward our proposal, while it renders a Hotelling's $T^2$ useless.

A sequential outlier detecting method using a clustering algorithm (군집 알고리즘을 이용한 순차적 이상치 탐지법)

  • Seo, Han Son;Yoon, Min
    • The Korean Journal of Applied Statistics
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    • v.29 no.4
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    • pp.699-706
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    • 2016
  • Outlier detection methods without performing a test often do not succeed in detecting multiple outliers because they are structurally vulnerable to a masking effect or a swamping effect. This paper considers testing procedures supplemented to a clustering-based method of identifying the group with a minority of the observations as outliers. One of general steps is performing a variety of t-test on individual outlier-candidates. This paper proposes a sequential procedure for searching for outliers by changing cutoff values on a cluster tree and performing a test on a set of outlier-candidates. The proposed method is illustrated and compared to existing methods by an example and Monte Carlo studies.

Studies on the Seed's Germinability test by the T.T.C. testing method. (T.T.C 검정방법에 의한 종자의 발아력검정에 관한 연구)

  • 전우방
    • Asian Journal of Turfgrass Science
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    • v.2 no.1
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    • pp.70-77
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    • 1988
  • In order to determine and to reduce the differences between biochemical test method for the seed viability with T.T.C. (2, 3, 5. Triphenyl tetrazolium Chloride) reagent and germinator method, the topographical diagram of red colored formazan was carried out in 15-16 parts differences. From this resulted information, the classification of the typical staining reaction given for 3 species were derived into 3-4 parts for the germinable in normal seedling, the same as the following results. 1. Corn (Gram inaceae) * Entier embryo stained in bright red color. * Both extremities of scutellum unstained * Both extremities of scuttlium, coleorhiza and non-critial portions of radicle unstained. 2. Soybean (Leguminosae) *Seed completely stained in red color. *Minor unstained areas on cotyledons. *Extreme tip of radicle unstained; minor unstained areas on cotyledons 3. Radish (Cruciferae) *Seed completely stained. *Minor unstained areas on cotyledons. *Outer cotyledon mostly unstained: inner cotyledon completely stained Extreme tip of radicle unstained: large portion of outer cotyledon unstained.

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Kullback-Leibler Information-Based Tests of Fit for Inverse Gaussian Distribution (역가우스분포에 대한 쿨백-라이블러 정보 기반 적합도 검정)

  • Choi, Byung-Jin
    • The Korean Journal of Applied Statistics
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    • v.24 no.6
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    • pp.1271-1284
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    • 2011
  • The entropy-based test of fit for the inverse Gaussian distribution presented by Mudholkar and Tian(2002) can only be applied to the composite hypothesis that a sample is drawn from an inverse Gaussian distribution with both the location and scale parameters unknown. In application, however, a researcher may want a test of fit either for an inverse Gaussian distribution with one parameter known or for an inverse Gaussian distribution with both the two partameters known. In this paper, we introduce tests of fit for the inverse Gaussian distribution based on the Kullback-Leibler information as an extension of the entropy-based test. A window size should be chosen to implement the proposed tests. By means of Monte Carlo simulations, window sizes are determined for a wide range of sample sizes and the corresponding critical values of the test statistics are estimated. The results of power analysis for various alternatives report that the Kullback-Leibler information-based goodness-of-fit tests have good power.

A study on alternatives to the permutation test in gene-set analysis (유전자집합분석에서 순열검정의 대안)

  • Lee, Sunho
    • The Korean Journal of Applied Statistics
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    • v.31 no.2
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    • pp.241-251
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    • 2018
  • The analysis of gene sets in microarray has advantages in interpreting biological functions and increasing statistical powers. Many statistical methods have been proposed for detecting significant gene sets that show relations between genes and phenotypes, but there is no consensus about which is the best to perform gene sets analysis and permutation based tests are considered as standard tools. When many gene sets are tested simultaneously, a large number of random permutations are needed for multiple testing with a high computational cost. In this paper, several parametric approximations are considered as alternatives of the permutation distribution and the moment based gene set test has shown the best performance for providing p-values of the permutation test closely and quickly on a general framework.

통계적 컬러영상처리를 이용한 사과의 색 선별 시스템 개발

  • Im, Dong-Hoon
    • Proceedings of the Korean Statistical Society Conference
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    • pp.143-148
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    • 2003
  • 본 논문에서는 통계적 방법에 기초한 사과 선별시스템을 이용하여 사과의 색깔을 식별하고자 한다. 이를 위해 T-검정을 이용하여 에지를 검출하였고 검출된 에지로부터 체인코드를 이용하여 사과 영상의 경계선과 환상대 영역을 구하였다. 우리는 주어진 사과영상의 환상대 영역으로부터 R, G, B 채널상에서 히스토그램과 평균 명암값을 구하여 색깔 판정용 표준사과로부터 얻은 기준값들과 비교함으로서 사과의 색깔을 식별하였다.

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Studies on the development of seed disinfectant in non-mercurious compounds (비유기수은 종자소독제개발에 관한 연구)

  • Lee Du-Hyung
    • Korean journal of applied entomology
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    • v.18 no.2
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    • pp.63-71
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    • 1979
  • Tests were made to find new non-mercurious seed disinfectants that were best for rice seeds. For these experiments four seed samples carr)?ing natural infection of Pyricularia oryzae, Helminthosporium oryzae, and Fusarium moniliforme were used and the following fungicides were used; Zinc Omadine, Sodium Omadine, Panoctine, Tecto-F, Benlate-T, Homai, Sisthane, $P_{242}$, Busan 30, Tecto-Wp and Terracoat Zn. Blotter method and water agar plate method used in the laboratory and growing-on test used in greenhouse. Results have shown that Sisthane, $P_{242}$ and Sodium Omadine have equal or superior effect to organic mercury compound against P. oryzae, H. oryzae, and F. moniliforme. Benlate T and Homai are effective against blast and Bakanae disease, but are inferior to organic mercury compound against brown spot disease. Busan 30 and Panoctine are effective against blast and brown spot disease, but have moderately inferior effects against F. monilifome. It is considered that the recommendable testing methods of seed treatment were blotter method for P. oryzae and water agar plate method for H, oryzae and F. moniliforme according to the experimental results obtained. No phytotoxicity against seed germination and seedling growth were observed when treated with disinfectants before germination of seeds.

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Trend and Shift Analysis for Hydrologic and Climate Series (수문 및 기후 자료에 대한 선형 경향성 및 평균이동 분석)

  • Oh, Je Seung;Kim, Hung Soo;Seo, Byung Ha
    • Journal of The Korean Society of Civil Engineers
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    • v.26 no.4B
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    • pp.355-362
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    • 2006
  • Several techniques of MK test, Spearman's Rho test, Linear Regression test, CUSUM test, Cumulative Deviation, Worsley Likelihood Ratio test, Rank Sum test, and Students' t test were applied to detect the trends of slope and shift which exist in hydrologic and climate time series. The time series of annual rainfall, inflow, tree ring index, and southern oscillation index (SOI) were used and the trends of these series were compared in the study. From the results, it can be found that the data could be classified into two categories such as linear trend and shift. 4 series data of 8 rainfall series which reveal the trend show the shift and 8 series data of 18 tree ring index and March and April series of monthly SOI data show shift. Moreover, ADF test and BDS test were used to test stationarity and non-linearity of the data. In conclusion, through the study, various trend analysis techniques were compared and 6 kinds of characteristics which can exist in hydrologic time series were identified.

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