Browsing Statistics by Issue Date

Browsing Statistics by Issue Date

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  • Depression in Kraepelinian schizophrenia 
    Naude, H.E.; Sykes, R.; Du Preez, Renata; Pretorius, H.W. (Herman Walter); Van der Linde, Michael J. (Mike); Pauw, J. (Health and Medical Publishing Group, 2009-12)
    OBJECTIVE: depressive symptoms are prevalent, underrecognised and clinically important in patients suffering from schizophrenia. Depressive symptoms in schizophrenia patients are associated with distinct morbidity and ...
  • Densities of composite Weibullized generalized gamma variables 
    Pauw, J.; Bekker, Andriette, 1958-; Roux, Jacobus J.J. (South African Statistical Association, 2010)
    The Weibullized generalized gamma distribution, which is a very exible distribution due to it richness in parameter structure, is derived by introducing the Weibullizing constant to the generalized gamma distribution. In ...
  • Markov processes in disease modelling : estimation and implementation 
    Marais, Christiaan Antonie (University of Pretoria, 2010)
    There exists a need to estimate the potential financial, epidemiological and societal impact that diseases, and the treatment thereof, can have on society. Markov processes are often used to model diseases to estimate these ...
  • Capital budgeting practices used by selected listed South African firms 
    Hall, J.H. (John Henry); Millard, Sollie M. (Juta, 2010-03)
    This article investigates the application of capital budgeting techniques and the incorporation of risk into the capital budgeting process among a sample of South African industrial firms listed on the JSE Securities ...
  • Modelling T4 cell count as a marker of HIV progression in the absence of any defense mechanism 
    Yadavalli, Venkata S. Sarma; Labeodan, Moremi Morire OreOluwapo; Udayabaskaran, Swaminathan; Forche, N. (Operations Research Society of SA, 2010-08)
    The T4 cell count, which is considered one of the markers of disease progression in an HIV infected individual, is modelled in this paper. The World Health Organisation has recently advocated that countries encourage HIV ...
  • An investigation into using neural networks for statistical classification and regression 
    Uys, Eben (University of Pretoria, 2010-09-22)
    Neural networks are seldom used as a modelling tool by statisticians. This is often due to the lack of knowledge in the eld of neural networks as neural networks are frequently perceived as mysterious methods that evolved ...
  • 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. ...
  • Interpolation in stationary spatial and spatial-temporal datasets 
    Smit, Ansie (University of Pretoria, 2010-10-27)
    In the early 1950s the study on how to determine true ore-grade distributions in the mining sector, sparked the development of a series of statistical tools that specifically allows for spatial and subsequently spatial-temporal ...
  • Meaningful batting averages in cricket 
    Van Staden, Paul Jacobus; Meiring, Albertus T.; Steyn, Johan A.; Fabris-Rotelli, Inger Nicolette (South African Statistical Association, 2010-11)
    In this paper we analyze and compare four different methods, designed to deal with the problem of an inflated batting average due to the presence of a high proportion of not-out innings. Batting records from the 2010 IPL ...
  • Evaluation of noise removal in signals by LULU operators 
    Fabris-Rotelli, Inger Nicolette; Van Oldenmark, K.; Van Staden, Paul Jacobus (South African Statistical Association, 2010-11)
    The LULU smoothers are effective nonlinear smoothers for signals. We investigate their ability to remove different noise types, namely symmetrical and skewed, as well as heavy- and light-tailed, thereby uncovering the true ...
  • D-optimal population designs for the simple linear random coefficients regression model 
    Debusho, Legesse Kassa; Haines, Linda M. (South African Statistical Association, 2010-11)
    In this paper D-optimal population designs for the simple linear random coefficients regression model with values of the explanatory variable taken from a set of equally spaced, non-repeated time points are considered. The ...
  • 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 ...
  • Analysis of wear-related failures in long-term follow-up of crosslinked polyethylene hip sockets 
    Grobbelaar, C.J.; Du Plessis, T.A.; Steffens, Francois E.; Van der Linde, Michael J. (Mike) (Media 24 & South African Orthopaedic Association, 2011)
    The publication of our long-term hip replacement follow-up study computer analysis has clearly demonstrated the association between polyethylene (polyethylene/UHMWPE) wear on the one hand and pain, interface widening and ...
  • Improved nonparametric control charts for location based on runs-rules 
    Kritzinger, Pierre (University of Pretoria, 2011)
    Numerous nonparametric or distribution-free control charts have been proposed and studied in recent years; see, for example, the overview articles by Chakraborti et al. (2001), Chakraborti and Graham (2007) and Chakraborti ...
  • A maximum likelihood estimation procedure for binary data from cross-over studies 
    Matthews, G.B. (Glenda Beverley); Crowther, N.A.S. (Nicolaas Andries Sadie), 1944- (South African Statistical Association, 2011)
    A maximum likelihood estimation procedure is presented for the expected frequencies when modelling binary data from two-period cross-over studies. This procedure provides a simple approach to parameter estimation in ...
  • Parameter structures in the exponential class 
    Strydom, H.F. (Hendrina Fredrika) (University of Pretoria, 2011)
    Maximum likelihood estimation of parameter structures in the exponential class is considered by using a procedure for maximum likelihood estimation under constraints. This procedure does not require maximization of the ...
  • Shannon entropy as a measure of certainty in a Bayesian calibration framework with bivariate beta priors 
    Bodvin, L.J.S.; Bekker, Andriette, 1958-; Roux, Jacobus J.J. (South African Statistical Association, 2011)
    The Bayesian estimator of the Shannon entropy is derived using Connor and Mosimann bivariate beta, bivariate beta type III and bivariate beta type V distribution distributions. Given the increased focus on the calculation ...
  • A stochastic point process model of the incubation period of a HIV infected individual 
    Yadavalli, Venkata S. Sarma; Labeodan, Moremi Morire OreOluwapo; Udayabaskaran, Swaminathan (South African Statistical Association, 2011)
    The inability to get people to regularly test and know their HIV status has caused the widespread unavailability of correct and comprehensive data on HIV infection especially the time at which an individual was first ...
  • Nuwe ontwikkeling tot die bivariate betaveld 
    Jacobs, Rianne; Bekker, Andriette, 1958-; Human, Schalk William (Suid Afrikaanse Akademie vir Wetenskap & Kuns, 2011)
    In this paper, the bivariate Kummer-beta type IV distribution, which extends the Jones’ bivariate beta distribution, is discussed. The probability density functions of the product and ratio of the components of this ...
  • Long-term evaluation of polyethylene wear in total hip replacement : a statistical analysis of the association between the degree of wear versus pain, interface change, osteopysis and implant failure 
    Grobbelaar, C.J.; Du Plessis, T.A.; Steffens, Francois E.; Van der Linde, Michael J. (Mike) (Media 24 & South African Orthopaedic Association, 2011)
    With over 3.5 decades dedicated exclusively to total joint replacement, our arthroplasty unit has repeatedly identified and reported a clear correlation between cup wear on the one hand, and pain, interface widening and ...