Afrika Statistika https://www.ajol.info/index.php/afst The Africa Statistika journal publishes applied and theoretical work researches about probabilities, statistics, operational research, financial mathematics and about the annexes as well. The fundamentals articles will be published in a series A, the applied articles in a series B. Each series will be displayed at least once per year. The articles are written in English or in French and have to be typed out with double spacing on the first side only, with a margin of three centimetres. The articles must not be longer than 12 pages. The invited papers can be longer. Other websites related to this journal:<a title=" www.jafristat.net" href="http://univi.net/jas/" target="_blank"> www.jafristat.net</a> Presses Universitaires de Saint-Louis en-US Afrika Statistika 2316-090X Copyright is owned by the journal A New Gamma Generalized Lindley-Loglogistic Distribution with Applications https://www.ajol.info/index.php/afst/article/view/204132 <p>A new distribution called the gamma exponentiated Lindley Log-logistic (GELLLoG) distribution is developed. Some properties of the new distribution including hazard function, quantile function, moments, conditional moments, mean and median deviations, Bonferroni and Lorenz curves, distribution of the order statistics and Renyi entropy are derived. Maximum likelihood estimation technique ยด is used to estimate the model parameters. We conduct a simulation study to examine the bias and mean square error of the maximum likelihood estimators. Finally, applications to real datasets to illustrate the usefulness of the proposed distribution are presented.</p> <p><strong>Key words:</strong> Gamma distribution; Lindley distributions: Exponentiated distribution: Long-logistic distribution: Generalized distribution: Maximum likelihood estimation </p> Thatayaone Moakofi Broderick Oluyede Boikanyo Makubate Copyright (c) 2021-02-22 2021-02-22 15 4 2451 2481 Half-Logistic Odd Weibull-Topp-Leone-G Family of Distributions: Model, Properties and Applications https://www.ajol.info/index.php/afst/article/view/204133 <p>A new flexible and versatile generalized family of distributions, namely, half logistic odd Weibull-Topp-Leone-G (HLOW-TL-G) distribution is presented. The distribution can be traced back to the exponentiated-G distribution. We derive the statistical properties of the proposed family of distributions. Maximum likelihood estimates of the HLOW-TL-G family of distributions are also presented. Five special cases of the proposed family are presented. A simulation study and real data applications on one of the special cases are also presented.</p> <p><strong>Key words</strong>: half-logistic-G; Topp-Leone-G; Odd Weibull-G; generalized distribution; maximum likelihood estimation</p> Fastel Chipepa Divine Wanduku Broderick Oluyede Copyright (c) 2021-02-22 2021-02-22 15 4 2481 2510 Adaptive Hyperbolic Asymmetric Power ARCH (A-HY-APARCH) model: Stability and Estimation https://www.ajol.info/index.php/afst/article/view/204134 <p>In this paper, a new asymmetric GARCH type model that generalizes the Hyperbolic Asymmetric Power ARCH (HY-APARCH) process is proposed. The proposed model takes into consideration some characteristics of financial time series data like volatility clustering, long memory and structural changes. The necessary and sufficient conditions for the asymptotic stability of the model are derived and parameter estimation methods are proposed. The Monte Carlo Simulations are done to prove the performance of the estimation method.</p> <p><strong>Key words</strong>: long range dependence; structural changes; HYAPARCH.&nbsp;</p> Charline Uwilingiyimana Abdou Ka Diongue Carlos Ogouyandjou Copyright (c) 2021-02-22 2021-02-22 15 4 2511 2528