• Title/Summary/Keyword: Statistical hypothesis

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Mitochondria Hypothesis on the Obesity-Prone Tendency in Tae-Eum People (태음인의 비만경향에 대한 미토콘드리아 가설)

  • Shim, Eun-Bo;Lee, Si-Woo;Kim, Sung-Joon;Leem, Chae-Hun;Kwon, Young-Kyu;Baik, You-Sang;Kim, Jong-Yeol;Earm, Yung-E.
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.23 no.6
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    • pp.1241-1246
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    • 2009
  • It has been suggested that Tae-Eum peoples are prone to obesity. Although extensive clinical observations have shown this tendency in Sasang Constitutional Medicine (SCM), no scientific hypothesis has been proposed to delineate its mechanism. According to SCM theory, Tae-Eum peoples have a hypoactive lung system and a hyperactive liver system. In this paper we propose a new hypothesis explaining the tendency of obesity in Tae-Eum people in the viewpoint of cell physiology. The hypoactive lung system might imply an attenuated 'respiration' at the cell/subcell level, namely mitochondrial oxygen consumption. Because a functional weakness in mitochondria energy metabolism indicates intrinsic hypo-activity in the consumption (or production) of metabolic energy, we deduced that the tendency can easily induce body weight gain via an increase in anabolism. This relation is also introduced in the graph of cellular metabolic power against body weight. To test this hypothesis, we analyzed the clinical data with 863 subjects. Statistical analysis of the data showed that Tae-Eum peoples had relatively a lower cellular metabolic power, and that the percentage of peoples with BMI>25 was significantly higher than that of the other constitutional types.

Major SNP Marker Identification with MDR and CART Application

  • Lee, Jea-Young;Choi, Yu-Mi
    • Communications for Statistical Applications and Methods
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    • v.15 no.2
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    • pp.265-271
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    • 2008
  • It is commonly believed that diseases of human or economic traits of livestock are caused not by single genes acting alone, but multiple genes interacting with one another. This issue is difficult due to the limitations of parametric-statistic methods of gene effects. So we introduce multifactor-dimensionality reduction(MDR) as a methods for reducing the dimensionality of multilocus information. The MDR method is nonparametric (i. e., no hypothesis about the value of a statistical parameter is made), model free (i. e., it assumes no particular inheritance model) and is directly applicable to case-control studies. Application of the MDR method revealed the best model with an interaction effect between the SNPs, SNP1 and SNP3, while only one main effect of SNP1 was statistically significant for LMA (p < 0.01) under a general linear mixed model.

Simultaneous Tests with Combining Functions under Normality

  • Park, Hyo-Il
    • Communications for Statistical Applications and Methods
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    • v.22 no.6
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    • pp.639-646
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    • 2015
  • We propose simultaneous tests for mean and variance under the normality assumption. After formulating the null hypothesis and its alternative, we construct test statistics based on the individual p-values for the partial tests with combining functions and derive the null distributions for the combining functions. We then illustrate our procedure with industrial data and compare the efficiency among the combining functions with individual partial ones by obtaining empirical powers through a simulation study. A discussion then follows on the intersection-union test with a combining function and simultaneous confidence region as a simultaneous inference; in addition, we discuss weighted functions and applications to the statistical quality control. Finally we comment on nonparametric simultaneous tests.

Structural Change and Stability in a Long-Run Parameter (장기모수의 구조변화와 안정성)

  • Kim, Tae-Ho
    • Communications for Statistical Applications and Methods
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    • v.18 no.4
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    • pp.495-505
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    • 2011
  • This study performs statistical tests for stability of a long-run relationship in the telecommunication market system by identifying the time path of a recursively estimated cointegration parameter. A dummy variable is used to recover stability for the period that the hypothesis of stable cointegration is rejected, and then a proper cointegrating relation is derived. A dummy variable appears to reflect the structural change in the cointegrating relation according to the analytical results for the error correction term.

Comparison of Some Nonparametric Statistical Inference for Logit Model (로짓모형의 비모수적 추론의 비교)

  • 정형철;김대학
    • The Korean Journal of Applied Statistics
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    • v.15 no.2
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    • pp.355-366
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    • 2002
  • Nonparametric statistical inference for the parameter of logit model were examined. Usually nonparametric approach is milder than parametric approach based on normal theory assumption. We compared the two nonparametric methods for legit model, the bootstrap and random permutation in the sense of coverage probability. Monte Carlo simulation is conducted for small sample cases. Empirical power of hypothesis test and coverage probability for confidence interval estimation were presented for simple and multiple legit model respectively. An example were also introduced.

The Limit Distribution of an Invariant Test Statistic for Multivariate Normality

  • Kim Namhyun
    • Communications for Statistical Applications and Methods
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    • v.12 no.1
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    • pp.71-86
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    • 2005
  • Testing for normality has always been an important part of statistical methodology. In this paper a test statistic for multivariate normality is proposed. The underlying idea is to investigate all the possible linear combinations that reduce to the standard normal distribution under the null hypothesis and compare the order statistics of them with the theoretical normal quantiles. The suggested statistic is invariant with respect to nonsingular matrix multiplication and vector addition. We show that the limit distribution of an approximation to the suggested statistic is representable as the supremum over an index set of the integral of a suitable Gaussian process.

The Limit Distribution and Power of a Test for Bivariate Normality

  • Kim, Namhyun
    • Communications for Statistical Applications and Methods
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    • v.9 no.1
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    • pp.187-196
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    • 2002
  • Testing for normality has always been a center of practical and theoretical interest in statistical research. In this paper a test statistic for bivariate normality is proposed. The underlying idea is to investigate all the possible linear combinations that reduce to the standard normal distribution under the null hypothesis and compare the order statistics of them with the theoretical normal quantiles. The suggested statistic is invariant with respect to nonsingular matrix multiplication and vector addition. We show that the limit distribution of an approximation to the suggested statistic is represented as the supremum over an index set of the integral of a suitable Gaussian Process. We also simulate the null distribution of the statistic and give some critical values of the distribution and power results.

Interval Estimation of the Difference of two Population Proportions using Pooled Estimator

  • Hong, Chong-Sun
    • Communications for Statistical Applications and Methods
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    • v.9 no.2
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    • pp.389-399
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    • 2002
  • In order to examine whether the difference between two point estimates of population proportions is statistically significant, data analysts use two techniques. The first is to explore the overlap between two associated confidence intervals. Second method is to test the significance which is introduced at most statistical textbooks under the common assumptions of consistency, asymptotic normality, and asymptotic independence of the estimates. Under the null hypothesis which is two population proportions are equal, the pooled estimator of population proportion is preferred as a point estimator since two independent random samples are considered to be collected from one population. Hence as an alternative method, we could obtain another confidence interval of the difference of the population proportions with using the pooled estimate. We conclude that, among three methods, the overlapped method is under-estimated, and the difference of the population proportions method is over-estimated on the basis of the proposed method.

BINGO: Biological Interpretation Through Statistically and Graph-theoretically Navigating Gene $Ontology^{TM}$

  • Lee, Sung-Geun;Yang, Jae-Seong;Chung, Il-Kyung;Kim, Yang-Seok
    • Molecular & Cellular Toxicology
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    • v.1 no.4
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    • pp.281-283
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    • 2005
  • Extraction of biologically meaningful data and their validation are very important for toxicogenomics study because it deals with huge amount of heterogeneous data. BINGO is an annotation mining tool for biological interpretation of gene groups. Several statistical modeling approaches using Gene Ontology (GO) have been employed in many programs for that purpose. The statistical methodologies are useful in investigating the most significant GO attributes in a gene group, but the coherence of the resultant GO attributes over the entire group is rarely assessed. BINGO complements the statistical methods with graph-theoretic measures using the GO directed acyclic graph (DAG) structure. In addition, BINGO visualizes the consistency of a gene group more intuitively with a group-based GO subgraph. The input group can be any interesting list of genes or gene products regardless of its generation process if the group is built under a functional congruency hypothesis such as gene clusters from DNA microarray analysis.

Derivation and Implementation of Statistical Difference and Practical Equivalence Models in the Quality Improvement Processes (품질개선 프로세스에서 통계적 차이와 실제적 동등성 모형의 유도 및 적용방안)

  • Choi, Sung-Woon
    • Journal of the Korea Safety Management & Science
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    • v.12 no.2
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    • pp.217-223
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    • 2010
  • The research proposes the complementary methodology using integrated hypothesis testing and confidence interval models that can be identified the statistical difference and practical equivalence. The models developed in this study can be used in the quality improvement processes such as QC story 15 steps. For the expressions of CI4LSD(Confidence Interval for Least Significant Difference) and CI4TOST(Confidence Interval for Two One-Sided Tests) are simple, quality practioners can efficiently handle them. CI4TOST models as a complement can be applied when CI4LSD models are influenced by sample size and precision.