• Title/Summary/Keyword: normality assumption

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On Effect of Nonnormality on Size of Test for Dimensionality in Discriminant Analysis

  • Changha Hwang
    • Communications for Statistical Applications and Methods
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    • v.3 no.3
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    • pp.25-30
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    • 1996
  • In discriminant analysis the procedures commonly used to estimate the dimensionality involve testing a sequence of dimensionality hypotheses. There is a problem with the size of the test since dimensionality hypotheses are tested sequentially and thus they are actually conditional tests. The focus of this paper is to investigate in asymptotic sense what happens to the sequential testing procedure if the assumption of normality does not hold.

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A Multi-period Behavioral Model for Portfolio Selection Problem

  • Pederzoli, G.;Srinivasan, R.
    • Journal of the Korean Operations Research and Management Science Society
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    • v.6 no.2
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    • pp.35-49
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    • 1981
  • This paper is concerned with developing a Multi-period Behavioral Model for the portfolio selection problem. The unique feature of the model is that it treats a number of factors and decision variables considered germane in decision making on an interrelated basis. The formulated problem has the structure of a Chance Constrained programming Model. Then empoloying arguments of Central Limit Theorem and normality assumption the stochastic model is reduced to that of a Non-Linear Programming Model. Finally, a number of interesting properties for the reduced model are established.

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Bayes Prediction Density in Linear Models

  • Kim, S.H.
    • Communications for Statistical Applications and Methods
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    • v.8 no.3
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    • pp.797-803
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    • 2001
  • This paper obtained Bayes prediction density for the spatial linear model with non-informative prior. It showed the results that predictive inferences is completely unaffected by departures from the normality assumption in the direction of the elliptical family and the structure of prediction density is unchanged by more than one additional future observations.

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A Test Procedure for Checking the Proportionality Between Hazard Functions

  • Lee, Seong-Won;Kim, Ju-Seong
    • Journal of the Korean Data and Information Science Society
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    • v.14 no.3
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    • pp.561-570
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    • 2003
  • We propose a nonparametric test procedure for checking the proportionality assumption between hazard functions using a functional equation. Because of the involvement of censoring distribution function, we consider the large sample case only and obtain the asymptotic normality of the proposeed test statistic. Then we discuss the rationale of the use of the functional equation, give some examples and compare the performances with Andersen's procedure by computing powers through simulations.

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SPECTRAL ANALYSIS OF TIME SERIES IN JOINT SEGMENTS OF OBSERVATIONS

  • Ghazal, M.A.;Elhassanein, A.
    • Journal of applied mathematics & informatics
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    • v.26 no.5_6
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    • pp.933-943
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    • 2008
  • Spectral analysis of a strictly stationary r-vector valued time series is considered under the assumption that some of the observations are missed due to some random failure. Statistical properties and asymptotic moments are derived. Asymptotic normality is discussed.

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Bayesian Estimation Procedure in Multiprocess Non-Linear Dynamic Normal Model

  • Sohn, Joong-Kweon;Kang, Sang-Gil
    • Communications for Statistical Applications and Methods
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    • v.3 no.1
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    • pp.155-168
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    • 1996
  • In this paper we consider the multiprocess dynamic normal model with parameters having a time dependent non-linear structure. We develop and study the recursive estimation procedure for the proposed model with normality assumption. It turns out thst the proposed model has nice properties such as insensitivity to outliers and quick reaction to abrupt changes of pattern.

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Percentile Envelope and Its Characteristic of Error Distribution for Supernormality

  • Lee, Jea-Young;Rhee, Seong-Won
    • Journal of the Korean Data and Information Science Society
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    • v.12 no.2
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    • pp.35-45
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    • 2001
  • We introduce a new percentile envelope for diagnosing supernormality in regression analysis. Furthermore, we compare this percentile envelope, which is much simpler and easier, with Atkinson's and Flack and Flores' envelopes. Using percentile envelope, we investigate characteristics of normal probability plots with envelope for error distributions when supernormality is occurred. We give cautions that test result for normality assumption of errors can be reached the wrong conclusion by supernormality.

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A Development of Elastoplastic Tangent Modulus in Finite Strain Space (변형율 공간에서의 탄소성 강도 매트릭스 형성)

  • 주관정
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1990.04a
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    • pp.70-74
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    • 1990
  • The finite plasticity in strain space is viewed by formulating the consistency condition and the thermodynamic condition with respect to proposed state variables. The Naghi-Trapp work assumption is used to obtain a constraint equation, and the normality equation is formulated. Finally, an elastoplastic tangent modulus, which is based on the derived equations in strain space, is proposed.

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A Generalized Likelihood Ratio Test in Outlier Detection (이상점 탐지를 위한 일반화 우도비 검정)

  • Jang Sun Baek
    • The Korean Journal of Applied Statistics
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    • v.7 no.2
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    • pp.225-237
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    • 1994
  • A generalized likelihood ratio test is developed to detect an outlier associated with monitoring nuclear proliferation. While the classical outlier detection methods consider continuous variables only, our approach allows both continuous and discrete variables or a mixture of continuous and discrete variables to be used. In addition, our method is free of the normality assumption, which is the key assumption in most of the classical methods. The proposed test is constructed by applying the bootstrap to a generalized likelihood ratio. We investigate the performance of the test by studying the power with simulations.

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Robust Bayesian analysis for autoregressive models

  • Ryu, Hyunnam;Kim, Dal Ho
    • Journal of the Korean Data and Information Science Society
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    • v.26 no.2
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    • pp.487-493
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    • 2015
  • Time series data sometimes show violation of normal assumptions. For cases where the assumption of normality is untenable, more exible models can be adopted to accommodate heavy tails. The exponential power distribution (EPD) is considered as possible candidate for errors of time series model that may show violation of normal assumption. Besides, the use of exible models for errors like EPD might be able to conduct the robust analysis. In this paper, we especially consider EPD as the exible distribution for errors of autoregressive models. Also, we represent this distribution as scale mixture of uniform and this form enables efficient Bayesian estimation via Markov chain Monte Carlo (MCMC) methods.