Research ArticleOpen accessIn the abstractNew Family of Logarithmic Lifetime DistributionsSaid Hofan AlkarniIn this study a new lifetime class with decreasing failure rate is introduced by compounding truncated logarithmic distribution with any proper continuous lifetime distribution. The properties of the proposed class are discussed, including a formal proof of itsprobability density function, distribution function and explicit algebraic formulae for its reliability and failure rate functions. A simple EM-type algorithm for iteratively computing … …Journal of Mathematics and Statistics, Vol. 8, Issue 4 · 20 Dec 2012 · 7,155 accessesView PDFCite
Research ArticleOpen accessIn the abstractOne-Sided Multivariate Tests for High Dimensional DataSamruam ChongcharoenProblem statement: For a multivariate normal population with size smaller than dimension, n<p, the likelihood ratio tests of the null hypothesis that the mean vector was zero with a one-sided alternative were no longer valid because they involved with sample covariance matrix which was singular. Approach: The test statistics for one-sided multivariate hypotheses with n<p were proposed. Results: The simulation … …Journal of Mathematics and Statistics, Vol. 8, Issue 2 · 20 Jun 2012 · 7,261 accessesView PDFCite
Research ArticleOpen accessIn the abstractEstimation of Genetic Correlations on Sweet Corn Inbred Lines Using SAS Mixed ModelPedram Kashiani, Ghizan SalehProblem statement: Genetic correlations among traits refer to the extent of relatedness among them due to genetic causes. Estimating genetic correlations for quantitative traits is tedious if done manually. Approach: However, the use of the computer software SAS, applying mixed-model analysis of variance has facilitated many recent studies in evolutionary quantitative genetics. Results: In this two-way statistical model, the variance … …American Journal of Agricultural and Biological Sciences, Vol. 5, Issue 3 · 30 Sep 2010 · 10,891 accessesView PDFCite
Research ArticleOpen accessIn the abstractComparison of Estimators of Dispersion MatrixNarges AbbasiBased on a sample, we considered the problem of estimating the dispersion matrix of a multivariate normal distribution with variance covariance matrix Σ. Empirical Bayes estimators and Haff estimators with their conditions, two proposed estimators of Σ, were the best affine equivariant estimators of dispersion matrix, which we compared them by three different loss functions. …Journal of Mathematics and Statistics, Vol. 4, Issue 3 · 31 Dec 2008 · 6,732 accessesView PDFCite
Research ArticleOpen accessIn the abstractSome Fast Methods for Fitting Some One-parameter Spatial ModelsR. J. MartinIt is common in geographic modelling to use a one-parameter spatial model to specify the inverse covariance matrix in terms of I-βW, for some known matrix W. Exact Gaussian maximum likelihood estimation of β requires evaluation of the determinant of the covariance matrix. For large data sets, this evaluation of the determinant can be slow and good approximations can be … …Journal of Mathematics and Statistics, Vol. 1, Issue 4 · 31 Dec 2005 · 6,066 accessesView PDFCite
Research ArticleOpen accessIn the abstractβ-Spline Estimation in a Semiparametric Regression Model with Nonlinear Time Series ErrorsJinhong You, Gemai Chen, Xian ZhouWe study the estimation problems for a partly linear regression model with a nonlinear time series error structure. The model consists of a parametric linear component for the regression coefficients and a nonparametric nonlinear component. The random errors are unobservable and modeled by a first-order Markov bilinear process. Based on a B-spline series approximation of the nonlinear component function, we … …American Journal of Applied Sciences, Vol. 2, Issue 9 · 30 Sep 2005 · 6,734 accessesView PDFCite