Browsing by Author "Barr, Graham Douglas Irving"

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    Applications and extentions of financial models to small markets : the South African case
    (1989) Bradfield, David John; Affleck-Graves , J F; Barr, Graham Douglas Irving
    ORGANIZATION OF THESIS: In Chapter 2, the important contributions to the development of Capital Market Theory will be discussed. Greater emphasis will be given to the more classical contributions and only a brief outline of the mathematical development will be presented where it is deemed necessary for the ensuing development of the thesis. In Chapter 3, a modified approach for portfolio selection in thinly-traded environments is proposed. This proposal concentrates on improving estimation of the inputs for practical implementation of the usual Markowitz portfolio selection routine. The estimation procedure adopted makes corrections for thin-trading and also makes use of the CAPM to improve the vector of return inputs. Chapter 4, basically consists of four sections. The first, gives a brief outline on historical estimation problems associated with the market model. In the second section the extent of thin-trading is investigated on the JSE. Furthermore a suitable beta estimation procedure which corrects for the effects of thin-trading is investigated empirically. In the third section an extended market model is proposed. This model leads to a more detailed, yet tractable structure of the risk components of stocks on smaller markets. An empirical investigation is subsequently conducted to investigate the risk structure of JSE stocks. In the last section of Chapter 4, an example of an empirical study using risk-adjusted returns is presented. The example considers the choice between bullion and South African gold shares from the international diversification perspective. In Chapter 5, empirical tests of the CAPM are conducted. This chapter consists of 2 main sections, namely, univariate tests and multivariate tests of the CAPM. Both of the tests also consider possible extensions of the CAPM by encorporating additional factors in the tests. Chapter 6 represents the main focus of this thesis, here the power of the univariate and multivariate tests of the CAPM are investigated using a simulation approach. The power investigation is conducted on simulated data that charaterizes the NYSE, however the JSE parameters are also considered. In the final section of this chapter the power of these tests are compared using various structured residual variance-covariance matrices. Lastly, some final thoughts and directions for future research are offered.
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    A contribution to adaptive robust estimation
    (1981) Barr, Graham Douglas Irving; Money, A H; Affleck-Graves , J F; Hart, M L;
    This study initially set out to consider the possibility of constructing an adaptive robust estimation procedure for the standard linear regression model when the disturbance vector deviated from normality, however, after the initial success in that field it seemed only appropriate that the approach be extended to robust location parameter estimation. This is a particular case of the regression model and an area in which a number of different estimators have been proposed and a great deal of comparative research work done. Due to the wider scope of such research the greater part of the thesis is devoted to this field of research which led to many interesting and useful results and conclusions.
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    Static and dynamic modelling of the South African real sector
    (1977) Barr, Graham Douglas Irving; Troskie, Casper G
    This thesis provides a detailed investigation of the applicability of various economic models to the South African real sector. It has been written primarily for the statistician, and thus presentation of economic theory has been in a straightforward and, if possible, mathematical form. Chapter One provides an introduction to the application of econometric methods to economic model building. Chapters Two, Three and Four consider the theory and application of various economic models to the South African case. Chapter Five considers the relevance of money to the real sector.