• Title/Summary/Keyword: Nonparametric statistical methods

Search Result 259, Processing Time 0.025 seconds

Nonparametric Procedures for Finding Minimum Effective Dose in a One-Way Layout

  • Kim, Hyeonjeong;Kim, Dongjae
    • Communications for Statistical Applications and Methods
    • /
    • v.9 no.3
    • /
    • pp.693-701
    • /
    • 2002
  • When the lowest dose level compared with zero-dose control has significant difference in effect, it is referred as minimum effective dose (MED). In this paper, we discuss several nonparametric methods for finding MED using updated rank at each sequential test step in small sample size and suggest new nonparametric procedures based on placement. Monte Carlo Simulation is adapted to compare power and Familywise Error Rate(FWE) of the new procedures with those of discussed nonparametric tests for finding MED.

Statistical Bias and Inflated Variance in the Genehunter Nonparametric Linkage Test Statistic

  • Song, Hae-Hiang;Choi, Eun-Kyeong
    • Communications for Statistical Applications and Methods
    • /
    • v.16 no.2
    • /
    • pp.373-381
    • /
    • 2009
  • Evidence of linkage is expressed as a decreasing trend of the squared trait difference of two siblings with increasing identical by descent scores. In contrast to successes in the application of a parametric approach of Haseman-Elston regression, notably low powers are demonstrated in the nonparametric linkage analysis methods for complex traits and diseases with sib-pairs data. We report that the Genehunter nonparametric linkage statistic is biased and furthermore the variance formula that they used is an inflated one, and this is one reason for a low performance. Thus, we propose bias-corrected nonparametric linkage statistics. Simulation studies comparing our proposed nonparametric test statistics versus the existing test statistics suggest that the bias-corrected new nonparametric test statistics are more powerful and attains efficiencies close to that of Haseman-Elston regression.

Optimal Designs for Multivariate Nonparametric Kernel Regression with Binary Data

  • Park, Dong-Ryeon
    • Communications for Statistical Applications and Methods
    • /
    • v.2 no.2
    • /
    • pp.243-248
    • /
    • 1995
  • The problem of optimal design for a nonparametric regression with binary data is considered. The aim of the statistical analysis is the estimation of a quantal response surface in two dimensions. Bias, variance and IMSE of kernel estimates are derived. The optimal design density with respect to asymptotic IMSE is constructed.

  • PDF

Nonparametric Bayesian methods: a gentle introduction and overview

  • MacEachern, Steven N.
    • Communications for Statistical Applications and Methods
    • /
    • v.23 no.6
    • /
    • pp.445-466
    • /
    • 2016
  • Nonparametric Bayesian methods have seen rapid and sustained growth over the past 25 years. We present a gentle introduction to the methods, motivating the methods through the twin perspectives of consistency and false consistency. We then step through the various constructions of the Dirichlet process, outline a number of the basic properties of this process and move on to the mixture of Dirichlet processes model, including a quick discussion of the computational methods used to fit the model. We touch on the main philosophies for nonparametric Bayesian data analysis and then reanalyze a famous data set. The reanalysis illustrates the concept of admissibility through a novel perturbation of the problem and data, showing the benefit of shrinkage estimation and the much greater benefit of nonparametric Bayesian modelling. We conclude with a too-brief survey of fancier nonparametric Bayesian methods.

Statistical methods used in articles published by the Journal of Periodontal and Implant Science

  • Choi, Eunsil;Lyu, Jiyoung;Park, Jinyoung;Kim, Hae-Young
    • Journal of Periodontal and Implant Science
    • /
    • v.44 no.6
    • /
    • pp.288-292
    • /
    • 2014
  • Purpose: The purposes of this study were to assess the trend of use of statistical methods including parametric and nonparametric methods and to evaluate the use of complex statistical methodology in recent periodontal studies. Methods: This study analyzed 123 articles published in the Journal of Periodontal & Implant Science (JPIS) between 2010 and 2014. Frequencies and percentages were calculated according to the number of statistical methods used, the type of statistical method applied, and the type of statistical software used. Results: Most of the published articles considered (64.4%) used statistical methods. Since 2011, the percentage of JPIS articles using statistics has increased. On the basis of multiple counting, we found that the percentage of studies in JPIS using parametric methods was 61.1%. Further, complex statistical methods were applied in only 6 of the published studies (5.0%), and nonparametric statistical methods were applied in 77 of the published studies (38.9% of a total of 198 studies considered). Conclusions: We found an increasing trend towards the application of statistical methods and nonparametric methods in recent periodontal studies and thus, concluded that increased use of complex statistical methodology might be preferred by the researchers in the fields of study covered by JPIS.

First Order Difference-Based Error Variance Estimator in Nonparametric Regression with a Single Outlier

  • Park, Chun-Gun
    • Communications for Statistical Applications and Methods
    • /
    • v.19 no.3
    • /
    • pp.333-344
    • /
    • 2012
  • We consider some statistical properties of the first order difference-based error variance estimator in nonparametric regression models with a single outlier. So far under an outlier(s) such difference-based estimators has been rarely discussed. We propose the first order difference-based estimator using the leave-one-out method to detect a single outlier and simulate the outlier detection in a nonparametric regression model with the single outlier. Moreover, the outlier detection works well. The results are promising even in nonparametric regression models with many outliers using some difference based estimators.

Nonparametric Bayesian Estimation for the Exponential Lifetime Data under the Type II Censoring

  • Lee, Woo-Dong;Kim, Dal-Ho;Kang, Sang-Gil
    • Communications for Statistical Applications and Methods
    • /
    • v.8 no.2
    • /
    • pp.417-426
    • /
    • 2001
  • This paper addresses the nonparametric Bayesian estimation for the exponential populations under type II censoring. The Dirichlet process prior is used to provide nonparametric Bayesian estimates of parameters of exponential populations. In the past, there have been computational difficulties with nonparametric Bayesian problems. This paper solves these difficulties by a Gibbs sampler algorithm. This procedure is applied to a real example and is compared with a classical estimator.

  • PDF