• Title/Summary/Keyword: Fisher's test

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Combining Independent Permutation p-Values Associated with Multi-Sample Location Test Data

  • Um, Yonghwan
    • Journal of the Korea Society of Computer and Information
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    • v.25 no.7
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    • pp.175-182
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    • 2020
  • Fisher's classical method for combining independent p-values from continuous distributions is widely used but it is known to be inadequate for combining p-values from discrete probability distributions. Instead, the discrete analog of Fisher's classical method is used as an alternative for combining p-values from discrete distributions. In this paper, firstly we obtain p-values from discrete probability distributions associated with multi-sample location test data (Fisher-Pitman test and Kruskall-Wallis test data) by permutation method, and secondly combine the permutaion p-values by the discrete analog of Fisher's classical method. And we finally compare the combined p-values from both the discrete analog of Fisher's classical method and Fisher's classical method.

The Comparison of the Unconditional and Conditional Exact Power of Fisher's Exact Tes

  • Kang, Seung-Ho;Park, Yoon-Soo
    • The Korean Journal of Applied Statistics
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    • v.23 no.5
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    • pp.883-890
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    • 2010
  • Since Fisher's exact test is conducted conditional on the observed value of the margin, there are two kinds of the exact power, the conditional and the unconditional exact power. The conditional exact power is computed at a given value of the margin whereas the unconditional exact power is calculated by incorporating the uncertainty of the margin. Although the sample size is determined based on the unconditional exact power, the actual power which Fisher's exact test has is the conditional power after the experiment is finished. This paper investigates differences between the conditional and unconditional exact power Fisher's exact test. We conclude that such discrepancy is a disadvantage of Fisher's exact test.

Combining Independent Permutation p Values Associated with Mann-Whitney Test Data

  • Um, Yonghwan
    • Journal of the Korea Society of Computer and Information
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    • v.23 no.7
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    • pp.99-104
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    • 2018
  • In this paper, we compare Fisher's continuous method with an exact discrete analog of Fisher's continuous method from permutation tests for combining p values. The discrete analog of Fisher's continuous method is known to be adequate for combining independent p values from discrete probability distributions. Also permutation tests are widely used as alternatives to conventional parametric tests since these tests are distribution-free, and yield discrete probability distributions and exact p values. In this paper, we obtain permutation p values from discrete probability distributions using Mann-Whitney test data sets (real data and hypothetical data) and combine p values by the exact discrete analog of Fisher's continuous method.

On Testing Fisher's Linear Discriminant Function When Covariance Matrices Are Unequal

  • Kim, Hea-Jung
    • Journal of the Korean Statistical Society
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    • v.22 no.2
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    • pp.325-337
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    • 1993
  • This paper propose two test statistics which enable us to proceed the variable selection in Fisher's linear discriminant function for the case of heterogeneous discrimination with equal training sample size. Simultaneous confidence intervals associated with the test are also given. These are exact and approximate results. The latter is based upon an approximation of a linear sum of Wishart distributions with unequal scale matrices. Using simulated sampling experiments, powers of the two tests have been tabulated, and power comparisons have been made between them.

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Hypothesis Testing: Means and Proportions (평균과 비율 비교)

  • Pak, Son-Il;Lee, Young-Won
    • Journal of Veterinary Clinics
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    • v.26 no.5
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    • pp.401-407
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    • 2009
  • In the previous article in this series we introduced the basic concepts for statistical analysis. The present review introduces hypothesis testing for continuous and categorical data for readers of the veterinary science literature. For the analysis of continuous data, we explained t-test to compare a single mean with a hypothesized value and the difference between two means from two independent samples or between two means arising from paired samples. When the data are categorical variables, the $x^2$ test for association and homogeneity, Fisher's exact test and Yates' continuity correction for small samples, and test for trend, in which at least one of the variables is ordinal is described, together with the worked examples. McNemar test for correlated proportions is also discussed. The topics covered may provide a basic understanding of different approaches for analyzing clinical data.

The Effect of Abdominal Massage on Sleep Colonoscopy Subjects (수면 대장내시경 검진자에게 시행한 복부마사지의 효과)

  • Lee, Yun-Jeong;Je, Nam-Joo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.6
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    • pp.410-420
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    • 2019
  • The purpose of this study is to investigate the effect of abdominal massage, on abdominal bloating and the recovery of bowel movement after sleep colonoscopy. The study design is the time difference before and after the non-equality control. The subjects were 22 patients each in experimental group and control group who recieved sleep colonoscopy at the G hospital in C city, The data collection period was from June 1, 2018 to August 25, 2018, and the control group's data were first collected with time difference from the collection of experimental group's data to prevent the spread of the experiment. Data were analyzed using IBM SPSS 24.0 and tested by independent sample t-test, $x^2-test$ and Fisher's exact probability test to verify the homogeneity of general characteristics of the subjects. Shapiro-Wilk was used to verify the normality of the abdominal circumference changes in the experimental and control groups. Mann-Whitney U test was used to verify the pre-homogeneity of the abdominal circumference of the subjects. The experimental results were verified by Fisher's exact probability test, Friedman test and Mann-Whitney U test. These results suggest that the abdominal massage can be used as a nursing intervention after sleep colonoscopy by reducing the gas discharge time($x^2=19.75$, p<.001) and abdominal bloating($x^2=29.93$, p<.001).

Statistical Study on Heredity in SaSang Constitutional Medicine (사상체질(四象體質)의 유전성(遺傳性) 검토(檢討)에 대한 통계적(統計的) 연구(硏究))

  • Kim, Dae-yun;Lee, Jae-won;Kim, Dal-rai
    • Journal of Sasang Constitutional Medicine
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    • v.11 no.1
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    • pp.159-168
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    • 1999
  • Purpose : Sasang Constitutional Medicine explains the pathology peculiar to constitution and suggests treatment for each constitution. In Sasang Constitutional Medicine hwnan beings are classified on four groups; Taeyangin, Taeumin, 5oyangin, Soeumin. These four constitution has their's own symptoms and treatments. In treatment, control of mind inclination, that is to say, moderation takes a very important role. But the study on heredity in Sasang Constitutional Medicine has not done not biological study but also statistical study. So we used several statistical methods and analyzed 163 samples. Methods : We implemented Fishers exact test for adjusting chi-squared test, kappa coefficient to estimate agreement of parent's and children's constitutions, and finally plotted bi-plot using correspondence analysis. Results : From Fisher's exact test result, we could know that parent's and children'S constitution's distribution had significant difference. In kappa coefficient, mother and daughter's estimated value produced highest result. In correspondence analysis we only plotted the case of mother and son for easy interpretation. Conclusion : In the study of heredity of SaSang constitution, we cannot know exactly the heredity of constitution in terms of biology or genetics. But this research can be helpful for further analysis, that is, a study of biological or genetical aspects. And we could conclude that in statistical aspects the heredity in SaSang constitution is meaningful.

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LVQ Network Design using SOM (SOM을 이용한 LVQ 네트워크 설계)

  • 김영렬;이용구;손동설;강성호;엄기환
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2002.11a
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    • pp.382-385
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    • 2002
  • We design LVQ network using SOM network for the LVQ's performance improvement. Reference vectors and the number of output neurons, they are the proposed LVQ network's initial parameters, are determined in SOM which is used for preprocessing LVQ. We simulate it to the grouping test of Fisher's Iris data. In this result, we confirm proposed LVQ network is better than existing LVQ in grouping test.

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A Study on the History of Statistics in the Early Twentieth Century Focused on Statistical Tests and Psychology (20세기 전반기 통계학사에 대한 연구 : 통계적 검정과 심리학을 중심으로)

  • Jo, Jae Keun
    • Journal for History of Mathematics
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    • v.26 no.4
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    • pp.277-299
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    • 2013
  • It was not until the early twentieth century that statistics emerged as an independent academic discipline. The developments of statistical theory and methods would not have been possible without heated controversies among founding fathers. One of them, controversy on the statistical test between R. A. Fisher and J. Neyman, E. S. Pearson had been very fierce and long-lasting. On the other hand it was in the early twentieth century that psychologists began to utilize statistical test which was a hybrid of tests developed by Fisher and Neyman-Pearson. By considering the history of fields such as psychology, we can see distinctive characteristics specific to the history of statistics.