• Title/Summary/Keyword: alternative hypothesis

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On Sample Size Calculation in Bioequivalence Trials

  • Kang, Seung-Ho
    • Proceedings of the PSK Conference
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    • 2003.04a
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    • pp.90-90
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    • 2003
  • Sample size calculations play an important role in bioequivalence trials. In almost all clinical trials sample size is determined by considering power under the alternative hypothesis. The alternative hypothesis is the hypothesis that we wish to prove with experiments. Hence, in bioequivalence trials the alternative hypothesis is that two formulations are bioequivalent, while the null hypothesis is that the two formulations are not bioequivalent. (omitted)

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A Study on Null Hypothesis and Alternative Hypothesis, Reduction to Absurdity and Application of Bayesian Statistics in Korean Medicine Otolaryngology (임상연구방법론에서 귀무가설과 대립가설, 귀류법에 대한 고찰과 한방이비인후과에서 베이지안 통계학의 활용)

  • Nam, Seung-Pyo;Bae, Jae-Min;Kwon, Kang
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.32 no.4
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    • pp.41-61
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    • 2019
  • Background : The current medical statistics used in clinical research are the results of Fisher's significance test and the Neyman-Pearson hypothesis test, which were combined by psychologists. Also, in the philosophical background, it is related to Popper's falsificationism based hypothesis-deductive method and reduction to absurdity. Objectives : This study was designed to find complementary and alternative methods of null hypothesis and alternative hypothesis used for the clinical research methodology of Korean medicine otolaryngology. Methods : The body of this paper was divided into seven part. These are historical background, hypothesis test, hypothesis test method used in the design of clinical study, falsificationism and reduction to absurdity, problem and alternative method of the Neyman-Pearson hypothesis test, diagnosis example of sinusitis differentiation syndromes by Bayesian statistics. Through this process, we found out problems of frequentist statistics and suggested alternative methods. Result & Conclusion : As a solution to the problems of the null hypothesis and the alternative hypothesis, there are effects size, confidence interval, Bayesian statistics and Lakatos methodology of scientific research programmes.

A Comparison of Scientists' and Students' Responses to Discrepant Event and Alternative Hypothesis in the Conceptual Change Processes from the Phlogiston Theory to the Oxygen Theory (플로지스톤설에서 산소설로의 개념 변화 과정에서 변칙 사례와 대안 가설에 대한 과학자들과 학생들의 반응 비교)

  • Noh, Tae-Hee;Yun, Jeong-Hyun;Kang, Hun-Sik;Kang, Suk-Jin
    • Journal of The Korean Association For Science Education
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    • v.26 no.7
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    • pp.798-804
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    • 2006
  • In this study, we investigated students' responses to a discrepant event and an alternative hypothesis which had been presented in the conceptual change processes from the phlogiston theory to the oxygen theory, and compared them with scientists' responses. The data concerning scientists' responses to the discrepant event and the alternative hypothesis were gathered from the relevant literature on the history of science. Subjects were 148 eighth graders who possessed the target misconception about combustion through a preconception test. After having been presented with the discrepant event and the alternative hypothesis, students were asked to respond to the test of response to discrepant event. Although similar types of responses were obtained from both scientists and students, there was also a clear difference. Scientists tended to focus on explaining the problems of the discrepant event, whereas students tended to ignore and/or exclude the discrepant event in order to maintain their previous beliefs. Only a few students were also found to change their beliefs after having been presented with the alternative hypothesis.

Influences of Cognitive Conflict and Non-cognitive Variables Induced by Discrepant Event and Alternative Hypothesis on Conceptual Change (변칙사례 및 대안가설에 의해 유발된 인지갈등과 비인지적 변인이 개념변화에 미치는 영향)

  • Kang, Hun-Sik;Kwack, Jin-Ha;Kim, You-Jung;Noh, Tae-Hee
    • Journal of the Korean Chemical Society
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    • v.51 no.1
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    • pp.56-64
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    • 2007
  • This study examined the influences of cognitive conflict and anxiety induced by a discrepant event and an alternative hypothesis, attention, and effort on conceptual change. Two hundred three students having misconceptions about density were selected from 462 seventh graders based on the results of a preconception test. Tests of cognitive responses and anxiety to a discrepant event were administered before and after presenting an alternative hypothesis. Computer-assisted instruction (CAI) was then provided to students as a conceptual change intervention. Tests assessing attention and effort allocated to the CAI, and conceptual understanding were administered as posttests. Cognitive conflict induced by a discrepant event was found to increase after presenting an alternative hypothesis. Pre-cognitive conflict induced by only a discrepant event exerted a direct effect on post-cognitive conflict induced by a discrepant event and an alternative hypothesis. Post-cognitive conflict had a direct effect on conceptual change. Pre-anxiety decreased after presenting an alternative hypothesis. Pre-anxiety influenced post-anxiety, and this influenced on conceptual change via effort negatively. Attention had a direct effect as well as an indirect effect on conceptual change via effort. These results suggest that the strategy presenting both a discrepant event and an alternative hypothesis to students in concept learning could facilitate conceptual change by inducing more cognitive conflict or active participation of students through the decrease of anxiety than that presenting a discrepant event only.

Multivariate Analysis of Variance for Fuzzy Data

  • Kang, Man-Ki;Han, Sung-Il
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.4 no.1
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    • pp.97-100
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    • 2004
  • We propose some properties of fuzzy multivariate analysis of variance by fuzzy vector operation with agreement index. We deals fuzzy null hypotheses and fuzzy alternative hypothesis and define the agreement index for the grades of the judgements that the hypothesis is rejection or acceptance. Finally, we provide an example to evaluate the judgements.

Computing Fractional Bayes Factor Using the Generalized Savage-Dickey Density Ratio

  • Younshik Chung;Lee, Sangjeen
    • Journal of the Korean Statistical Society
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    • v.27 no.4
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    • pp.385-396
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    • 1998
  • A computing method of fractional Bayes factor (FBF) for a point null hypothesis is explained. We propose alternative form of FBF that is the product of density ratio and a quantity using the generalized Savage-Dickey density ratio method. When it is difficult to compute the alternative form of FBF analytically, each term of the proposed form can be estimated by MCMC method. Finally, two examples are given.

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Test of the Hypothesis based on Nonlinear Regression Quantiles Estimators

  • Choi, Seung-Hoe
    • Journal of the Korean Data and Information Science Society
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    • v.14 no.2
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    • pp.153-165
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    • 2003
  • This paper considers the likelihood ratio test statistic based on nonlinear regression quantiles estimators in order to test of hypothesis about the regression parameter $\theta_o$ and derives asymptotic distribution of proposed test statistic under the null hypothesis and a sequence of local alternative hypothesis. The paper also investigates asymptotic relative efficiency of the proposed test to the test based on the least squares estimators or the least absolute deviation estimators and gives some examples to illustrate the application of the main result.

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Statistical Approach for AESA Radar Maximum Detection Range (AESA 레이더 최대탐지거리의 통계적 접근)

  • Tak, Daesuk;Shin, Kyung Soo
    • Journal of the Korean Society of Systems Engineering
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    • v.15 no.1
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    • pp.43-50
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    • 2019
  • Statistical hypothesis tests are important for quantifying answers to questions about samples of data. The Step Process of Statistical Hypothesis Testing; state the null hypothesis, State the alternate hypothesis, State the alpha level, Find the z-score associated with alpha level, Find the test statistic using this formula, If the calculated t distribution value from the data is larger than the t distribution value of alpha level, then you are in the Rejection region and you can reject the Null Hypothesis with ($1-{\alpha}$) level of confidence.

Impostor Detection in Speaker Recognition Using Confusion-Based Confidence Measures

  • Kim, Kyu-Hong;Kim, Hoi-Rin;Hahn, Min-Soo
    • ETRI Journal
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    • v.28 no.6
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    • pp.811-814
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    • 2006
  • In this letter, we introduce confusion-based confidence measures for detecting an impostor in speaker recognition, which does not require an alternative hypothesis. Most traditional speaker verification methods are based on a hypothesis test, and their performance depends on the robustness of an alternative hypothesis. Compared with the conventional Gaussian mixture model-universal background model (GMM-UBM) scheme, our confusion-based measures show better performance in noise-corrupted speech. The additional computational requirements for our methods are negligible when used to detect or reject impostors.

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Utterance Verification Using Search Confusion Rate and Its N-Best Approach

  • Kim, Kyu-Hong;Kim, Hoi-Rin;Hahn, Min-Soo
    • ETRI Journal
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    • v.27 no.4
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    • pp.461-464
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    • 2005
  • Recently, a variety of confidence measures for utterance verification has been studied to improve speech recognition performance by rejecting out-of-vocabulary inputs. Most of the conventional confidence measures for utterance verification are based primarily on hypothesis testing or an approximated posterior probability, and their performances depend on the robustness of an alternative hypothesis or the prior probability. We introduce a novel confidence measure called a search confusion rate (SCR), which does not require an alternative hypothesis or the approximation of posterior probability. Our confusion-based approach shows better performance in additive noise-corrupted speech as well as in clean speech.

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