• Title, Summary, Keyword: t-검정

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혼합설계의 교호작용에 대한 여러 검정법들과 결사평균을 이용하여 변형한 검정법들의 강인성 비교

  • 김현철
    • Communications for Statistical Applications and Methods
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    • v.5 no.3
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    • pp.633-644
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    • 1998
  • 혼합설계의 교호작용에 대한 F 검정이 유효하려면 다표본 구형성(multisample sphericity) 가정과 다변량 정규분포 가정이 만족되어야 한다. F 검정을 실시하기 위한 가정들이 위반된 조건하에서 혼합설계의 교호작용에 대한 검정법들의 1종오류가 비교되었다. 비교된 검정법들은 (1) F 검정(F), (2) 절사평균을 사용한 F 검정($F_T$)(3)$\varepsilon$-수정 F 검정($\varepsilon)$(4) 절사평균을 사용한 $\varepsilon$-수정 F 검정$(\varepsilon_T$) (5) CIGA검정(CIGA), (6) 절사평균을 사용한 CIGA검정($CIGA_T$)이었다. 결과는 CIGA와 $CIGA_T$는 1종오류를 대체로 잘 관리하나, F검정들과 ($\varepsilon$)검정들은 일부 조건에서 아주 작은 1종오류나 아주 큰 1종오류를 갖는 것으로 나타났다.

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Statistical methods for testing tumor heterogeneity (종양 이질성을 검정을 위한 통계적 방법론 연구)

  • Lee, Dong Neuck;Lim, Changwon
    • The Korean Journal of Applied Statistics
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    • v.32 no.3
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    • pp.331-348
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    • 2019
  • Understanding the tumor heterogeneity due to differences in the growth pattern of metastatic tumors and rate of change is important for understanding the sensitivity of tumor cells to drugs and finding appropriate therapies. It is often possible to test for differences in population means using t-test or ANOVA when the group of N samples is distinct. However, these statistical methods can not be used unless the groups are distinguished as the data covered in this paper. Statistical methods have been studied to test heterogeneity between samples. The minimum combination t-test method is one of them. In this paper, we propose a maximum combinatorial t-test method that takes into account combinations that bisect data at different ratios. Also we propose a method based on the idea that examining the heterogeneity of a sample is equivalent to testing whether the number of optimal clusters is one in the cluster analysis. We verified that the proposed methods, maximum combination t-test method and gap statistic, have better type-I error and power than the previously proposed method based on simulation study and obtained the results through real data analysis.

Power Test of Trend Analysis using Simulation Experiment (모의실험을 이용한 경향성 분석기법의 검정력 평가)

  • Ryu, Yongjun;Shin, Hongjoon;Kim, Sooyoung;Heo, Jun-Haeng
    • Journal of Korea Water Resources Association
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    • v.46 no.3
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    • pp.219-227
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    • 2013
  • Time series data including change, jump, trend and periodicity generally have nonstationarity. Especially, various methods have been proposed to identify the trend about hydrological time series data. However, among various methods, evaluation about capability of each trend test has not been done a lot. Even for the same data, each method may show the different result. In this study, the simulation was performed for identification about the changes in trend analysis according to the statistical characteristics and the capability in the trend analysis. For this purpose, power test for the trend analysis is conducted using Men-Kendall test, Hotelling-Pabst test, t test and Sen test according to the slope, sample size, standard deviation and significance level. As a result, t test has higher statistical power than the others, while Mann-Kendall, Hotelling-Pabst, and Sen tests were similar results.

Two-sample Tests for Edge Detection in Noisy Images (잡음영상에서 에지검출을 위한 이표본 검정법)

  • 임동훈;박은희
    • 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.

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RegARIMA 모형을 이용한 음력 명절효과의 검정에 관한 연구

  • Mun, Gwon-Sun
    • Proceedings of the Korean Statistical Society Conference
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    • pp.73-77
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    • 2005
  • 본 논문은 시계열에 내재된 설${\cdot}$추석 등 음력 명절효과의 존재를 검정하기 위해 RegARIMA 모형의 잔차에 대한 t-검정 통계량을 제시하였으며 Box-plot에 의한 그래프적 진단을 시도하였다. 제시된 t-검정 결과를 X-12-ARIMA의 AICC-사전검정 및 RegARIMA 모형에 의해 추정된 명절효과 회귀계수의 t-값과 비교하였다. 사용된 명절효과 변수는 Bell과 Hillmer(1983)의 명절효과 변수이다.

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Note on the Equality of Variances in Two Sample t-Test (두 집단 평균 차이 검정에서 분산의 동질성에 관한 소고)

  • Kim, Sang-Cheol;Lim, Jo-Han
    • Communications for Statistical Applications and Methods
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    • v.17 no.1
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    • pp.79-88
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    • 2010
  • Introductory statistic class proposes two tests for the equality of two population means according to the homogeneity of their variances. However, in practice, the variances are also unknown and practitioners often test their homogeneity before they do two sample t-test. This is also true in many popular statistical packages such as SAS and SPSS. In this paper, we study the type I error of this two stage procedure and propose a procedure to control it at a given significance level.

A minimum combination t-test method for testing differences in population means based on a group of samples of size one (크기가 1인 표본들로 구성된 집단에 기반한 모평균의 차이를 검정하기 위한 최소 조합 t-검정 방법)

  • Heo, Miyoung;Lim, Changwon
    • The Korean Journal of Applied Statistics
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    • v.30 no.2
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    • pp.301-309
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    • 2017
  • It is often possible to test for differences in population means when two or more samples are extracted from each N population. However, it is not possible to test for the mean difference if one sample is extracted from each population since a sample mean does not exist. But, by dividing a group of samples extracted one by one into two groups and generating a sample mean, we can identify a heterogeneity that may exist within the group by comparing the differences of the groups' mean. Therefore, we propose a minimum combination t-test method that can test the mean difference by the number of combinations that can be divided into two groups. In this paper, we proposed a method to test differences between means to check heterogeneity in a group of extracted samples. We verified the performance of the method by simulation study and obtained the results through real data analysis.

Window Configurations Comparison Based on Statistical Edge Detection in Images (영상에서 윈도우 배치에 따른 통계적 에지검출 비교)

  • Lim, Dong-Hoon
    • Communications for Statistical Applications and Methods
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    • v.16 no.4
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    • pp.615-625
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    • 2009
  • In this paper we describe Wilcoxon test and T-test that are well-known in two-sample location problem for detecting edges under different window configurations. The choice of window configurations is an important factor in determining the performance and the expense of edge detectors. Our edge detectors are based on testing the mean values of local neighborhoods obtained under the edge model using an edge-height parameter. We compare three window configurations based on statistical tests in terms of qualitative measures with the edge maps and objective, quantitative measures as well as CPU time for detecting edge.

Sample Size Determination for One-Sample Location Tests (일표본 위치검정에서의 표본크기 결정)

  • Yeo, In-Kwon
    • The Korean Journal of Applied Statistics
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    • v.28 no.3
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    • pp.573-581
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    • 2015
  • We study problems of sample size determination for one-sample location tests. A simulation study shows that sample size calculations based on approximated distribution do not achieve the nominal level of power. We investigate sample size determinations based on exact distribution and with a power that attains the nominal level.

한국산 검정망둑(Tridentiger obscurus)과 민물검정망둑(T.brevispinis)의 분류학적 고찰

  • 김종범;양서영
    • Animal Systematics, Evolution and Diversity
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    • v.11 no.3
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    • pp.359-377
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    • 1995
  • Morphological and isozyme analyses were used to examine closely related species of Tridentiger obscurus and \ulcorner: brevispinis, a pair of cryptic species which has intricate problem with regard to species boundary, and to clarify the taxonomic position. In this study, it was revealed from their 17 allopatric streams that there are differences of band ornamentation on the lateral side and three genetic markers between two species. However, genetic relationship between them (S = 0.813, D = 0.192) was within the intraspecific level of similarity. However, at the sympatry of two species no hybrid was found except at Bangjuk stream where the electrophoretic hybrids with slight deficiency of heterozygosity were observed. It is shown that at sympatry there is a finer microenvironmental subdivision between two species at all populations including Bangjuk stream. To manifest the extent of assortative mating, four syrnpatric subpopulations at Bangjuk stream were analyzed for departure from Hardy-Weinberg equillibrium by F-statistics. All subpopulations were deviated significantly from the expectation under random mating. The evidences presented here supports the recognition of Tridentiger obscurus and T. brevispinis as semispecies in the late stage of reproductive isolation

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