• 제목/요약/키워드: statistical hypothesis test

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UMP Unbiased Test for the Infection Rate in Group Testing

  • Kwon, Se-hyug
    • Communications for Statistical Applications and Methods
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    • 제6권1호
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    • pp.293-303
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    • 1999
  • When test outcomes of units are dichotomous and he infection rate is small group testing is more efficient that noe-to-one testing in estimating the true p and classifying units as infected or not. In this paper two-sided hypothesis testing and confidence intervals are derived based on the UMP(uniformly most powerful) unbiased test. The UMP unbiased approach is compared with Thompson's and Bhattacharyya et al.'s approaches by computing the length of confidence intervals and capture probabilities and shown to have a number of desirable properties. Unequal allocation one of advantages of the proposed approach is also mentioned.

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정보제공과 음악요법이 심혈관조영술 환자의 불안에 미치는 영향 (Deducing Coronary Artery Disease Anxiety through Musical Therapy and Providing Information)

  • 강미숙;박경민;박청자
    • 대한간호학회지
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    • 제30권2호
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    • pp.380-390
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    • 2000
  • This study was performed to evaluate the effectiveness of music therapy as one of the psychiatric nursing intervention tools, with addtional information in relieving anxiety during the procedure. Data were collected through nonequivalent pre-and post tests from July 1, 1998 to September 30 1998 in 90 patients (test group A: 28 patients, test group B: 27 patients, control group: 33 patients) who were hospitalized in DongSan Medical Center in order to have cardiac catheterization. The Subjects were informed by educational videos, which were modified according to the sensory information of the 10 study patients. They were based on the informative booklet by Kim keum-soon (1989). The procedural information was also modified according to the hospital`s customs. Provided the music for patients suitable to their tastes, and measured their blood pressure, heart rate, the degree of anxiety using the Spielberger`s measurement device of anxiety, and behavioral response of Finesilver`s. The statistical significance was analyzed using chi-square test and ANOVA. The results of this study were as follows : Hypothesis 1 : There are significant differences in the degree of anxiety among test group A, Test group A was provided only information, Test group B was provided information and the control group was provided neither. Hypothesis 2 : There are significant differences in systolic blood pressure among test group A, test group B, and control group.: non-significant. Hypothesis 3 : There are significant differences in diastolic blood pressure among test group A, test group B, and control group.: significant(F=1.31, p=.27, interaction; F=3.80, p=.00). Hypothesis 4 : There are significant differences in heart rate among test group A, test group B, and control group.: non-significant. Hypothesis 5 : There are significant differences in behavioral responses among test group A, test group B, and control group.: significant(F=10.05, p=.00). Further validation study is required with other subjects and other settings.

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Some Nonparametric Tests for Change-points with Epidemic Alternatives

  • Kim, Kyung-Moo
    • Communications for Statistical Applications and Methods
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    • 제4권2호
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    • pp.427-434
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    • 1997
  • The purpose of this paper is to discuss distribution-free tests of hypothesis that the random samples are identically distributed against the epidemic alternative. But most tests that have been considered are depended only on specific null distribution. Two nonparametric tests are considered and compared with a likelihood ratio test by the empirical powers.

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비디오 객체 생성을 위한 자동 영상 분할 방법 (An Automatic Segmentation Method for Video Object Plane Generation)

  • 최재각;김문철;이명호;안치득;김성대
    • 방송공학회논문지
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    • 제2권2호
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    • pp.146-155
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    • 1997
  • 본 논문은 MPEG-4와 같이 객체 및 내용 기반 영상 부호화에 필요한 동영상의 자동 영역 분할 알고리즘을 제안한다. 통계적 가설 검증(statistical hypothesis test)을 사용하여 영상 시퀀스내에 포함된 비디오 객체들(video objects)을 움직임 물체(moving objects)와 배경 (background)으로 자동 분할하는 새로운 영상 분할 알고리즘을 제안한다. 기존 방법들이 두 개의 연속된 영상을 사용하는 반면에, 제안된 방법은 3개의 연속된 영상을 사용하여, 2개의 차영상의 평균값을 비교하여 가설검증을 행함으로써 잡음에 강한 특성을 나타낸다. 그리고 제안된 방법은 기존 방법과는 달리 참분산(true variance)을 사전에 알고 있을 필요가 없는 장점을 갖고 있다[18]. 또한 시간정보만을 이용한 변화 검출 방법의 문제점인 불규칙하고 부정확한 영역의 경계를 공간정보를 이용하여 보정하는 새로운 방법을 제안한다. 시험 결과에서 주어진 것처럼 제안된 시공간정보를 이용한 영상 분할 알고리즘이 시각적으로 의미있는 분할 결과를 제공함을 알 수 있고, 정확한 영역 경계를 추출할 수 있기 때문에 MPEG-4와 같은 객체 기반 영상 부호화에 적용할 경우에 영역 경계에서 상당히 우수한 재생 화질을 얻을 수 있다.

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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.

Genetic association tests when a nuisance parameter is not identifiable under no association

  • Kim, Wonkuk;Kim, Yeong-Hwa
    • Communications for Statistical Applications and Methods
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    • 제24권6호
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    • pp.663-671
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    • 2017
  • Some genetic association tests include an unidentifiable nuisance parameter under the null hypothesis of no association. When the mode of inheritance (MOI) is not specified in a case-control design, the Cochran-Armitage (CA) trend test contains an unidentifiable nuisance parameter. The transmission disequilibrium test (TDT) in a family-based association study that includes the unaffected also contains an unidentifiable nuisance parameter. The hypothesis tests that include an unidentifiable nuisance parameter are typically performed by taking a supremum of the CA tests or TDT over reasonable values of the parameter. The p-values of the supremum test statistics cannot be obtained by a normal or chi-square distribution. A common method is to use a Davies's upper bound of the p-value instead of an exact asymptotic p-value. In this paper, we provide a unified sine-cosine process expression of the CA trend test that does not specify the MOI and the TDT that includes the unaffected. We also present a closed form expression of the exact asymptotic formulas to calculate the p-values of the supremum tests when the score function can be written as a linear form in an unidentifiable parameter. We illustrate how to use the derived formulas using a pharmacogenetics case-control dataset and an attention deficit hyperactivity disorder family-based example.

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

  • 조재근
    • 한국수학사학회지
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    • 제26권4호
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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.

Double Unit Root Tests Based on Recursive Mean Adjustment and Symmetric Estimation

  • Shin, Dong-Wan;Lee, Jong-Hyup
    • Journal of the Korean Statistical Society
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    • 제30권2호
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    • pp.281-290
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    • 2001
  • Symmetric estimation and recursive mean adjustment are considered to construct tests for the doble unit root hypothesis for both parametric and semiparametric time series models. It is shown that simultaneous application of symmetric estimation and recursive mean adjustment yields the most powerful test. Moreover, size property of the semiparametric test based on the simultaneous application is bet among all semiparametric tests.

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Heteroscedasticity of Random Effects in Crossover Design

  • 안철환
    • 한국통계학회:학술대회논문집
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    • 한국통계학회 2002년도 추계 학술발표회 논문집
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    • pp.79-83
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    • 2002
  • A phase III clinical trial of a new drug for neutropenia induced by chemotherapy is presented and consider adding random effects in crossover design which was used in the clinical study. The diagnostics for its heteroscedasticity based on score statistic is derived for detecting homoscedasticity of errors in crossover design. A small simulation study is peformed to investigate the finite sample behaviour of the test statistic which is known to have an asymptotic chi-square distribution under the null hypothesis.

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동조화 현상의 견인차 가설 검정과 분석 (Test and Analysis for Comovement-Locomotive Hypothesis)

  • 김태호
    • 응용통계연구
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    • 제24권2호
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    • pp.239-251
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    • 2011
  • 국가 간 경기 동조화 현장은 한 나라의 경기변동이 긴 시차를 두지 않고 관련국의 경기와 금융시장의 변동으로 직결되면서 동반 이동이 어떤 형태를 보이는지에 대한 통계적 분석의 필요성이 중대하고 있다. 본 연구에서는 동조화 현상과 파급효과에 대한 견인차 가설에 입각해 규모가 큰 경제가 작은 규모 국가의 변동을 유발하는지의 여부와 성향을 파악하고자 한 미 양국의 현재와 미래의 경기동향 및 주식시장 간 장기적 역학관계와 구조적 성향에 대해 통계적으로 검정해 보았다. 국내 주식시장에는 국내 경기동향이나 미국의 현 경기여건보다는 미국의 미래 경기전망이 유의한 영향을 미치는 것으로 나타났다.