• 제목/요약/키워드: Fisher Exact Test

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

  • Kang, Seung-Ho;Park, Yoon-Soo
    • 응용통계연구
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    • 제23권5호
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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
    • 한국컴퓨터정보학회논문지
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    • 제23권7호
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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.

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

  • 이윤정;제남주
    • 한국산학기술학회논문지
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    • 제20권6호
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    • pp.410-420
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    • 2019
  • 본 연구는 수면 대장내시경 검진자에게 복부마사지를 시행하여 장운동 회복과 복부팽만감에 미치는 효과를 파악하기 위하여 시도된 비동등성 대조군 전후 시차설계연구이다. 연구대상자는 C시, G병원에서 외래를 통해 수면 대장내시경 검진을 받는 실험군 22명, 대조군 22명으로 자료 수집 기간은 2018년 6월 1일부터 8월 25일까지였으며, 실험의 확산효과를 막기 위하여 대조군을 먼저 자료수집 한 후 시차를 두고 실험을 실시하였다. 자료분석은 IBM SPSS 24.0을 이용하여 자료를 분석하였으며, 대상자의 일반적 특성의 동질성을 검증하기 위하여 독립표본 t-test, $x^2-test$ 와 Fisher's exact probability test, 실험군, 대조군의 복부둘레 변화량에 대한 정규성을 검증하기 위하여 Shapiro-Wilk로 검증, 복부둘레의 사전 동질성을 검증하기 위하여 Mann-Whitney U test를 실시하였다. 실험처치 효과 검증은 Fisher's exact probability test, Friedman test와 Mann-Whitney U test로 검증하였다. 연구 결과, 복부마사지가 대장내시경 검진자의 가스배출 시간($x^2=19.75$, p<.001)과 복부팽만감($x^2=29.93$, p<.001)을 감소시켜, 수면 대장내시경 검진자의 가스팽만으로 인한 불편감을 완화하는 간호중재로 활용할 수 있을 것으로 생각된다.

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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    • 제22권2호
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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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사상체질(四象體質)의 유전성(遺傳性) 검토(檢討)에 대한 통계적(統計的) 연구(硏究) (Statistical Study on Heredity in SaSang Constitutional Medicine)

  • 김대윤;이재원;김달래
    • 사상체질의학회지
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    • 제11권1호
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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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저산소 뇌 손상에서의 뇌량 미세출혈 (Microbleeds in the Corpus Callosum in Anoxic Brain Injury)

  • 김창수;박동우;김태윤;이영준;이지영
    • 대한영상의학회지
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    • 제81권5호
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    • pp.1184-1193
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    • 2020
  • 목적 뇌량 미세출혈이 저산소 뇌 손상과 상관관계가 있는지 알아보고자 하였다. 대상과 방법 임상적으로 진단된 27명의 저산소 뇌 손상 환자군을 대상으로 후향적으로 연구를 진행하였다. 나이와 성별을 매칭한 대조군과 Fisher's exact test로 동반 질환, 뇌 미세출혈 유무를 비교하였다. 환자군은 뇌량 미세출혈의 유무로 나누어 비교하였다. Fisher's exact test로 두 그룹 간의 저산소 뇌 손상의 전형적인 자기공명영상 특징 유무, 심폐소생술 유무, 예후 정도를 비교하였고, Mann-Whitney U test로 저산소 뇌 손상 사건 발생 후 자기공명영상 획득까지의 시간 간격을 비교하였다. 결과 환자군에서 뇌 미세출혈은 29.6%에서 보였으며, 이는 대조군의 3.7%보다 통계적으로 유의하게 높았다(p = 0.012). 환자군에서의 모든 뇌 미세출혈은 뇌량에 국한됐다. 비뇌량 미세출혈군과 비교하여, 뇌량 미세출혈군은 좋은 예후를 보이는 경우가 많았고(6/8 vs. 11/19), 저산소 뇌 손상의 전형적인 자기공명영상 특징을 작은 비율에서 보이며(2/8 vs. 10/19), 심폐소생술이 많은 비율에서 시행됐으나(6/8 vs. 12/19) 통계적 유의성을 보이진 못하였다(p = 0.35, p = 0.19, p = 0.45, respectively). 결론 뇌량 미세출혈은 저산소 뇌 손상을 시사하는 부수적인 자기공명영상 특징이 될 수 있겠다.

평균과 비율 비교 (Hypothesis Testing: Means and Proportions)

  • 박선일;이영원
    • 한국임상수의학회지
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    • 제26권5호
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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.

United Kingdom pediatric dentistry specialist views on the administration of articaine in children

  • Ezzeldin, Maryam;Hanks, Gemma;Collard, Mechelle
    • Journal of Dental Anesthesia and Pain Medicine
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    • 제20권5호
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    • pp.303-312
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    • 2020
  • Background: Lidocaine is the gold standard local anesthetic (LA) for UK pediatric dental treatment. Recent reports suggest frequent Articaine use in Europe and Canada, with evidence indicating more profound anesthesia. The aim of this study was to examine pediatric dentistry specialist experiences and practices relating to Articaine administration in the UK. Methods: A literature review was followed by a survey using an anonymous 15-item electronic questionnaire, which was sent to 200 registered British Society of Pediatric Dentistry (BSPD) specialists. Descriptive analyses, Z score, chi-squared test, Fisher's exact test, and Spearman's correlation test were performed. Results: Sixty-one (30.5%) participants responded, and 12 (19.7%) indicated Articaine as their first line anesthetic. Articaine was used daily or weekly by 38 (62.3%) respondents, depending on the clinical context. Articaine was commonly used to avoid inferior alveolar nerve blocks and gain more profound anesthesia in abscessed or hypomineralized teeth. Participants reported significantly more adverse effects with lidocaine (Fisher's exact test, P < 0.0001) than with Articaine. Articaine was most often administered in children aged > 4 years via infiltration techniques. Only 15 (24.6%) respondents reported awareness of guidelines for Articaine use in pediatric patients. Conclusions: Articaine use in pediatric dentistry is common; however, evidence supporting its practice is limited. Several specialists follow conventions based on anecdotal evidence. Formulating guidance to aid decision-making when treating pediatric patients under LA would be beneficial.

The effect of the tongue in groove technique on the nasolabial angle and nasal tip projection

  • Khabir, Fatemeh;Sezavar, Mehdi;Bohluli, Behnam;Mesgarzadeh, Vahid;Tavakoli, Hamidreza
    • Maxillofacial Plastic and Reconstructive Surgery
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    • 제42권
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    • pp.19.1-19.4
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    • 2020
  • Background: The tongue in groove technique (TIG) is a useful technique for the correction of the nasal tip projection and the nasolabial angle. The purpose of this study was to determine the utility of this technique for nasal tip rotation and projection correction in the Iranian society. Methods: This is a retrospective clinical trial study of 20 patients undergoing open septo-rhinoplasty using TIG technique from January 2017 to August 2019 at the oral and maxillofacial unit of Bu Ali Hospital and private sector. Preoperative and postoperative profile view photographs were compared to assess the changes in tip projection and rotation. Results: Fifteen patients (75%) had normal angular size, and 5 of them (25%) were not within the normal range after the surgery. The Fisher exact test showed that this success was statistically significant (P = 0.006). Ten patients (50%) had normal projection size, postoperatively. The Fisher exact test showed that this effect was statistically significant (P < 0.01) Conclusion: The study demonstrated the benefit of TIG on the correction of nasal tip projection and rotation.