Browsing Theses and Dissertations (Statistics) by Type "Dissertation"

Browsing Theses and Dissertations (Statistics) by Type "Dissertation"

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  • A spatial variant of the Gaussian mixture of regressions model 
    Delport, Marion (University of Pretoria, 2017)
    In this study the nite mixture of multivariate Gaussian distributions is discussed in detail including the derivation of maximum likelihood estimators, a discussion on identi ability of mixture components as well as a ...
  • Accelerated testing with application in finance 
    Oppel, Anel (University of Pretoria, 2016)
    The event of a default for low-default portfolios, such as sovereign debt or banks, have received much attention as a result of the increasing instabilities in financial markets. The lack of sufficient default information ...
  • Adaboost and its application using classification trees 
    Vithal, Nishay (University of Pretoria, 2013)
    This mini-dissertation seeks to provide the reader with an understanding of one of the most popular boosting methods in use today called Adaboost and its first extension Adaboost.M1. Boosting, as the name suggests, is an ...
  • Alternative methods to parametric significance testing in linear regression and ANOVA 
    Makhanya, Nhlanhla Well-Beloved (University of Pretoria, 2015)
    The aim of the study was to survey permutation tests, bootstrapping and jackknife methods and their application to significance testing of regression coefficients in linear regression analysis. A Monte Carlo simulation ...
  • Alternative parametric considerations for direction and distance when modelling animal movement 
    Ramkilawon, Gopika Devi (University of Pretoria, 2022-02-06)
    Animal movement is a fundamental part of ecology, and aids in understanding and modelling of social responsibility phenomena including population and community structure dynamics. Movement of animals is often characterised ...
  • Bayesian convolutional neural networks : a probabilistic approach to address uncertainty in convolutional neural networks with an application in image processing 
    Steyn, Carl (University of Pretoria, 2018)
    Neural Networks (NNs) play an integral role in modern machine learning development. Recent advances in NN research have led to a wide array of applications, ranging from medical diagnosis [1] to complex problems such as ...
  • Bayesian estimation of Shannon entropy for bivariate beta priors 
    Bodvin, Joanna Sylvia Liesbeth (University of Pretoria, 2010-09-22)
    Having just survived what is arguably the worst financial crisis in time, it is expected that the focus on regulatory capital held by financial institutions such as banks will increase significantly over the next few years. ...
  • Bayesian kernel density estimation 
    Rademeyer, Estian (University of Pretoria, 2017)
    This dissertation investigates the performance of two-class classi cation credit scoring data sets with low default ratios. The standard two-class parametric Gaussian and naive Bayes (NB), as well as the non-parametric ...
  • Big data : a compressed sensing approach 
    Janse van Rensburg, Charl (University of Pretoria, 2017)
    In recent times Big Data has been talked about in many areas, ranging from information technology, to government and healthcare, and to business. Big Data is changing the world we live in in many respects, especially as ...
  • The bootstrap approach to autoregressive time series analysis 
    De Koster, Felicia Henriette (University of Pretoria, 2006-11-20)
    Please read the abstract in the section 00front of this document Accompanied by 1 disc available at main counter with shelf number EM 519.5 DE KOSTER. Master copy at back of book
  • Causal Inference : controlling for bias in observational studies using propensity score methods 
    Msibi, Mxolisi (University of Pretoria, 2020)
    Adjusting for baseline pre-intervention characteristics between treatment groups, through the use of propensity score matching methods, is an important step that enables researchers to do causal inference with confidence. ...
  • Comparing logistic regression methods for completely separated and quasi-separated data 
    Botes, Michelle (University of Pretoria, 2013)
    An occurrence which is sometimes observed in a model based on dichotomous dependent variables is separation in the data. Separation in the data is when one or more of the independent variables can perfectly predict some ...
  • The compounding method for finding bivariate noncentral distributions 
    Ferreira, Johannes Theodorus (University of Pretoria, 2014-04)
    The univariate and bivariate central chi-square- and F distributions have received a decent amount of attention in the literature during the past few decades; the noncentral counterparts of these distributions have been ...
  • Computational aspects of hierarchical mixture models for geological data 
    Laidlaw, Michaela (University of Pretoria, 2021)
    Buidling off a foundation of knowledge from studies into modelling wind speed, models are fitted to multimodal datasets of geological nature. Mixtures of distributions are derived with parameter updates done via ...
  • Construction and parameter estimation of wrapped normal models 
    Roux, Hannaline (University of Pretoria, 2019)
    If a known distribution on a real line is given, it can be wrapped on the circumference of a unit circle. This research entails the study of a univariate skew-normal distribution where the skew-normal distribution is ...
  • Contributions to control charts for attributes data 
    Shongwe, Sandile Charles (University of Pretoria, 2014)
    No abstract
  • Customer Value Management Using the Cox Additive Regression Model 
    van Wyk de Vries, Jan (University of Pretoria, 2013)
    The Cox-Proportional Hazards model is introduced as a potential tool to understand customer behavior relating to churn or disconnections in the telecommunications space. An overview of Survival Analysis is provided along ...
  • Data Compression and Quantization 
    Du Toit, Benjamin David (University of Pretoria, 2014)
    Data Compression Due to limitations in data storage and bandwidth, data of all types has often required compression. This need has spawned many different methods of compressing data. In certain situations the fidelity of ...
  • Dependence structures in multidimensional arrays 
    Lau, Kwok-Ho (University of Pretoria, 2016)
    In the process of data acquisition the information obtained are more than often contaminated by noise. To purify the data smoothers are designed to remove the noise. The LULU operators are such smoothers, more speci ...
  • The development of the quaternion normal distribution 
    Loots, Mattheus Theodor (University of Pretoria, 2010-12-28)
    In this dissertation an overview on the real representation of quaternions in distribution theory is given. The density functions of the p-variate and matrix-variate quaternion normal distributions are derived from first ...