Browsing by Author "Yahya, Waheed"

Now showing 1 - 4 of 4
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    Applications of some Exponential Related Distributions
    (Proceedings of the Professional Statisticians Society of Nigerian, 2019) Umar, M. A.; Jimoh, J.O.; Garba, Mohammed; Afolayan, Razaq; Yahya, Waheed
    Exponential family of distribution is a very popular family of distribution functions for analyzing any lifetime data with a lot of applications in different fields of knowledge. This family has distribution functions whose survival, hazard and mean residual life functions are simple and easy to study. As a result, this family has been generalized, modified and mixed with other density functions to give more flexible density functions to facilitate better modeling and analysis. This study is carried out to apply some of these distributions to real life datasets from clinical sciences, remission times of a Bladder cancer dataset. The behaviours of these distributions were illustrated graphically. The parameters of the distributions were estimated using the maximum likelihood method and their goodness-of-fits were examined. The distributions were found to provide satisfactory fits to the datasets considered. Exponentiated Exponential and Exponential-Gamma distributions were found to perform better than all the competing distributions.
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    Bayesian Estimation of Kumaraswamy Distribution under Different Loss Functions.
    (Professional Statisticians Society of Nigeria(PSSN)., 2019) Adegoke, T. M.; Nasiri, P; Adegoke, G. K.; Yahya, Waheed; Afolayan, Razaq
    In this study, the procedures of Bayesian estimation of the shape parameter of the Kumaraswamy distribution under different prior distributions are examined. The shape parameter of the Kumaraswamy distribution is assumed to follow noninformative prior distributions (such as the extension of Jeffrey’s prior distribution, Hartigan Prior distribution, and Uniform Prior distribution) and the informative prior distribution (such as the Gamma distribution and Inverted levy distribution) were adopted in this work. We compared the obtained estimates using their mean square errors under different loss functions (such as precautionary loss function, Squared error loss function, and Albayyati’s loss function). The results showed that the behaviour of the Bayesian estimations of the shape parameter of the Kumaraswamy distribution under the Squared Error loss function using Inverted levy prior distribution is the best among all the prior distributions considered.
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    Multivariate Time Series Analysis on the Prices of Staple Foodstuffs in Kwara State, Nigeria
    (Department of Science Education, Federal University of Technology Minna., 2016) Afolayan, Razaq; Yahya, Waheed; Garba, Mohammed; Adenuga, A. A.; Olatayo, T.
    Due to supplementary, complementary and substitute relationship between staple foodstuffs, the prices of one or more staple foodstuffs tend to influence and could be used to predict the prices of some others. This study was therefore aimed at establishing the co-movement between the prices of some major stable foodstuffs - Rice, Maize, Garri, Millet, Guinea-Corn and Beans - in Kwara State, Nigeria. Multivariate time series models were fitted to data on monthly prices of Rice, Maize, Garri, Millet, Guinea-Corn and Beans over a period of twelve years (from January 2000 to December 2012). The cointegration relations among the prices were established by applying Johansen’s cointegration tests. As a result, appropriate Vector Error Correction (VEC) model was fitted to the data. The unit root test for stationarity in the series reveals that all the series were non-stationary but they were only made to be stationary at first difference. The results from the analysis showed that there exist short term adjustments and long-term dynamics among the prices of Rice, Maize, Garri, Millet, Guinea-Corn and Beans in Nigeria over the study period. Further results showed that a Vector Error Correction (VEC) model of lag two with one cointegration equation best fits the data. The forecasting accuracy of the fitted model was determined by out-of-sample forecasts of the future prices of the selected staple foodstuffs. Suitable model’s assessment criteria such as root mean square error, mean absolute error and the like were employed to determine the efficiency of the fitted model. The data employed for the study were collected from the Kwara State office of National Bureau of Statistics, Nigeria. All analyses were performed in the environment of R Statistical package.
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    On the Strength of Agreement between Initial and Final Academic performances in a Nigerian University System
    (ABACUS, Mathematical Association of Nigeria, 2018) Banjoko, Alabi; Yahya, Waheed; Abiodun, H. S.; Afolayan, Razaq; Garba, Mohammed; Olorede, K. O.; Dauda, K.A.; Adeleke, Mariam O.
    This paper examines the strength of agreement between academic performances of students after their first and final years in the University. Academic performances of a total of 886 students that were admitted into various academic programs in the Faculty of Science, University of Ilorin, during the 2008/2009 academic session were followed-up to their year of graduation in 2012. Information on the grade point average (GPA) of students at the end of their first year in 2008, their final cumulative grade point average (CGPA) at the end of their studies in 2012 among others were collected. Results from this study generally showed a fair agreement between students’ initial and final academic performances in Nigeria University system (p < 0.001). It was also found that about 50% of students maintained the classes of degrees they had in their first year till graduation, about 40% of them improved on their performances while the performances of about 7% of them dropped from what they had at their first year. Further results showed that students’ performance is gender sensitive. Specifically, about 45% and 60% of female and male students maintained the classes of degrees they had during their first year in the University, about 50% and 30% of them improved on theirs while about 5% and 10% of them dropped from their initial academic performances at the end of their studies respectively. Finally, students in the Biological Sciences improved on their initial academic performances more than their counterparts in the Physical Sciences. Also, female students improved on their initial academic performances more than their male counterparts. This work will serve as useful counselling guide to prospective admission seekers into the Universities and all the stakeholders at enhancing students’ academic performances in the University system.