Gafar Matanmi Oyeyemi

@unilorin.edu.ng

Professor of Statistics, Head of Department, Department of Statistics, Faculty of Physical Sciences
Department of Statistics, University of Ilorin



                       

https://researchid.co/matanmi

RESEARCH, TEACHING, or OTHER INTERESTS

Statistics and Probability, Statistics, Probability and Uncertainty

4

Scopus Publications

502

Scholar Citations

11

Scholar h-index

11

Scholar i10-index

Scopus Publications

  • On development of four-parameters exponentiated generalized exponential distribution


  • On discrimination procedure with mixtures of continuous and categorical variables
    Gafar Matanmi Oyeyemi, George Chinanu Mbaeyi, Saheed Ishola Salawu, and Bernard Olagboyega Muse
    Informa UK Limited
    ABSTRACT A discrimination procedure, based on the location model is described and suggested for use in situation where the discriminating variables are mixtures of continuous and binary variables. Some procedures that have been previously employed, in a similar situation, like Fisher's linear discriminant function and the logistic regression were compared with this method using error rate (ER). Optimal ERs for these procedures are reported using real and simulated data for the case of varying sample size and number of continuous and binary variables and were used as a measure for assessing the performance of the various procedures. The suggested procedure performed considerably better in the cases considered and never did produce a result that is poor when compared with other procedures. Hence, the suggested procedure might be considered for such situations.

  • Trace elements; Copper, zinc and selenium, in breast cancer afflicted female patients in LAUTECH Osogbo, Nigeria
    ML Adeoti, AS Oguntola, EO Akanni, OS Agodirin, and GM Oyeyemi
    Medknow
    BACKGROUND There is an indication of the possibility of the direct or indirect influence of trace element in the development and prevention of malignant diseases, the contribution of the trace elements in the etiology of breast cancer has been under scrutiny. AIMS The aim of this study was to determine the serum concentration of trace element in serum of female patients with breast cancer in comparison with healthy controls. SETTINGS Breast Clinic of the Department of Surgery LAUTECH University teaching hospital Osogbo, in south-western Nigeria. MATERIALS AND METHODS A cross-sectional age matched controlled prospective study wherein the venous blood sample of 30 patients with breast cancer and 30 healthy volunteers as controls were analyzed using atomic absorption spectrophotometry. The collected data were analyzed using statistical package for the social sciences (SPSS Inc) 16. RESULT The mean serum concentration of the copper, zinc and selenium were 95.3 ± 4.9 ug/dl and 65.2 ± 15 ug/dl, 62.7 ± 15.7 ug/dl and 93.5 ± 7.2 ug/dl, 45.0 ± 4.6 ug/l and 76.4 ± 8.9 ug/l in the two groups respectively. The concentrations of copper and copper-zinc ratio (C/Z) were significantly higher in the cancer bearing group compared to the controls (C/Z 1.6 ± 0.5 against 0.70 ± 0.14 the P < 0.01). The concentration of zinc and selenium in the venous blood of the breast cancer patients showed inverse relationship while that of the control showed a direct relationship (-0.03 against 0.09). In the breast cancer patients the correlation of copper and zinc, copper and selenium and zinc and selenium showed inverse relationships, none of the relationships was statistically significant. CONCLUSION We found a significant association between the serum concentration of trace elements and breast cancer.

  • An examination of some safety issues among commercial motorcyclists in Nigeria: A case study
    Godwin Tunde Arosanyin, Adekunle Taiwo Olowosulu, and Gafar Matanmi Oyeyemi
    Informa UK Limited
    The reduction of road crashes and injuries among motorcyclists in Nigeria requires a system inquiry into some safety issues at pre-crash, crash and post-crash stages to guide action plans. This paper examines safety issues such as age restriction, motorcycle engine capacity, highway code awareness, licence holding, helmet usage, crash involvement, rescue and payment for treatment among commercial motorcyclists. The primary data derived from a structured questionnaire administered to 334 commercial motorcyclists in Samaru, Zaria were analysed using descriptive statistics and logistic regression technique. There was total compliance with age restriction and motorcycle engine capacity. About 41.8% of the operators were not aware of the existence of the highway code. The odds of licence holding increased with highway code awareness, education with above senior secondary as the reference category and earnings. The odds of crash involvement decreased with highway code awareness, earnings and mode of operation. About 84% of the motorcyclists did not use crash helmet, in spite of being aware of the benefit, and 65.4% of motorcycle crashes was found to be with other road users. The promotion of safety among motorcyclists therefore requires strict traffic law enforcement and modification of road design to segregate traffic and protect pedestrians.

RECENT SCHOLAR PUBLICATIONS

  • A new reduced contagious zero-inflated model: An application to count data
    MI Adarabioyo, GM Oyeyemi
    ABUAD International Journal of Natural and Applied Sciences 3 (2), 1-15 2023

  • ALTERNATIVE ESTIMATOR IN THE ANALYSIS OF VARIANCE TECHNIQUE IN THE PRESENCE OF OUTLIERS
    AK Odior, GM Oyeyemi
    The Journals of the Nigerian Association of Mathematical Physics 65, 217-224 2023

  • REVIEW OF SOME ROBUST ESTIMATORS IN MULTIPLE LINEAR REGRESSIONS IN THE PRESENCE OF OUTLIER (s)
    T Alanamu, GM Oyeyemi, RO Olaniran, KO Adetunji
    African Journal of Mathematics and Statistics Studies 2023

  • Combined exponential-type estimators for finite population mean in two-phase sampling
    GM Oyeyemi, I Muhammad, AO Kareem
    Asian Journal of Probability and Statistics 21 (2), 44-58 2023

  • Performance of Generalized Autoregressive Conditional Heteroscedasticity (GARCH) Models in Modeling Volatility of Brent Crude Oil Price
    SD Gbolagade, GM Oyeyemi, AO Abidoye, TJ Adejumo, AI Okegbade
    Ilorin Journal of Science 9 (1), 20-32 2022

  • Spatial Analysis of Distribution of Inmates in Nigeria Prisons
    GM Oyeyemi, AO Kareem, EEO Alemika, AB Ibraheem, OM Oladuti
    Ilorin Journal of Science 8 (1), 21-35 2021

  • REGULARIZATION TECHNIQUES IN MULTIPLE LINEAR REGRESSION IN THE PESENCE OF MULTICOLLINEARITY
    OA Oyegoke, GM Oyeyemi, MO Adeleke, RO Kolawole
    FULafia Journal of Science and Technology 6 (1), 48-53 2020

  • PROPOSED HOTELLING’S T2 CONTROL CHARTS BASED ON LOCATION AND SCATTER MATRIX
    OS Obafemi, GM Oyeyemi, FA Bolarinwa
     2020

  • An Empirical Study on the Run Length Properties of the Side-Sensitive Modified Group Runs Double Sampling (SSMGRDS) Control Chart for Monitoring the Process Mean Shifts
    AA Umar, SS Abubakar, HG Dikko, A Yahaya, GM Oyeyemi, JY Falgore, ...
    Academic Research Society of Malaysia 2020

  • A Comparison of some Discriminant Techniques in Predicting Blood Pressure
    T Yussuf, BL Adeleke, GM Oyeyemi, MO Adeleke, AO Kareem
    Faculty of Science, University of Ibadan, Nigeria 2019

  • Comparison of Some Spike-and-Slab Priors for Bayesian Variable Selection in Multiple Linear Regression
    GM Oyeyemi, YA Olanrewaju, RO Kolawole
    Akamai University, USA 2019

  • ON THE ESTIMATION OF EMPTY CELL PROBABILITIES IN A CONTINGENCY TABLE
    GM Oyeyemi, GC Mbaeyi
    Annals. Computer Science Series 16 (1) 2018

  • Stand-in Procedure to Multivariate Behrens-Fisher Problem
    GM Oyeyemi, PO Adebayo
    European Journal of Statistics and Probability 6 (1), 16-28 2018

  • Alternative estimator for multivariate location and scatter matrix in the presence of outlier
    OS Obafemi, GM Oyeyemi
    Anale Seria Informatica 2018

  • Heteroscedasticity in One Way Multivariate Analysis of Variance
    GM Oyeyemi, PO Adebayo, BL Adeleke
    J Phys Math 9 (270), 2090-0902.1000270 2018

  • Parametric and Pattern Recognition Models for Credit Scoring in Banking System
    S Oyeyemi, G. M. and Issa
    Journal of the Nigerian Association of Mathematical Physics 44 (1), 163 - 174 2018

  • An Alternative Least Trimmed Squares Estimation of Regression Parameters in the Presence of Outliers in the Independent Variables
    AK Oyeyemi, G. M. and Odior
    Journal of the Nigerian Association of Mathematical Physics 44 (1), 163 - 174 2018

  • An Alternative Solution to Hotelling T Square under the Heteroscedasticity of the Dispersion Matrix
    PO Adebayo, GM Oyeyemi
    Department of Statistics, University of Ilorin, Ilorin, Nigeria. The Pacific 2018

  • Pak. J. Statist. 2018 Vol. 34 (4), 331-358 ON DEVELOPMENT OF FOUR-PARAMETERS EXPONENTIATED GENERALIZED EXPONENTIAL DISTRIBUTION
    A Bukoye, GM Oyeyemi
    Pak. J. Statist 34 (4), 331-358 2018

  • A new robust method for estimating linear regression model in the presence of outliers
    T Alanamu, GM Oyeyemi
    Pacific Journal of Science and Technology 19 (1), 125-132 2018

MOST CITED SCHOLAR PUBLICATIONS

  • Trace elements; copper, zinc and selenium, in breast cancer afflicted female patients in LAUTECH Osogbo, Nigeria
    ML Adeoti, AS Oguntola, EO Akanni, OS Agodirin, GM Oyeyemi
    Indian journal of cancer 52 (1), 106-109 2015
    Citations: 68

  • On performance of shrinkage methods–a Monte Carlo Study
    GM Oyeyemi, EO Ogunjobi, AI Folorunsho
    International Journal of Statistics and Applications 5 (2), 72-76 2015
    Citations: 67

  • Employment generation and earnings in the informal transport sector in Nigeria
    GT Arosanyin, AT Olowosulu, GM Oyeyemi
    International Business and Management 2 (2), 139-148 2011
    Citations: 55

  • Compliance with Road Safety Regulations Among Commercial Motorcyclists in Nigeria/Conformite a la Reglementation de la Securite Routiere Parmi Les Motocyclistes Au Nigeria
    AG Tunde, OA Taiwo, OG Matanmi
    Canadian Social Science 8 (1), 92 2012
    Citations: 45

  • Comparison of outlier detection procedures in multiple linear regressions
    GM Oyeyemi, A Bukoye, I Akeyede
    American Journal of Mathematics and Statistics 5 (1), 37-41 2015
    Citations: 33

  • Complex survey data analysis: a comparison of SAS, SPSS and STATA
    GM Oyeyemi, AA Adewara, RA Adeyemi
    Asian J Math Stat 3, 33-9 2010
    Citations: 33

  • On the estimation of power and sample size in test of independence
    GM Oyeyemi, AA Adewara, FB Adebola, SI Salau
    nil 2010
    Citations: 31

  • An examination of some safety issues among commercial motorcyclists in Nigeria: a case study
    GT Arosanyin, AT Olowosulu, GM Oyeyemi
    International journal of injury control and safety promotion 20 (2), 103-110 2013
    Citations: 26

  • How effective is the treatment of locally advanced and metastatic breast cancer in developing centres?: A retrospective review
    O Agodirin, S Olatoke, G Rahman, M Adeoti, G Oyeyemi, A Durojaiye, ...
    Ethiopian journal of health sciences 25 (4), 337-344 2015
    Citations: 16

  • Poverty in the urban informal sector of Kwara state, Nigeria
    GT Ijaiya, RA Bello, GT Arosanyin, GM Oyeyemi, UA Raheem, AT Yakubu
    Department of Economics, Faculty of Social Sciences, University of Ilorin 2015
    Citations: 12

  • A robust method of estimating covariance matrix in multivariate data analysis
    GM Oyeyemi, RA Ipinyomi
    African Journal of Mathematics and Computer Science Research 3 (1), 1-18 2010
    Citations: 12

  • Combined exponential-type estimators for finite population mean in two-phase sampling
    GM Oyeyemi, I Muhammad, AO Kareem
    Asian Journal of Probability and Statistics 21 (2), 44-58 2023
    Citations: 9

  • Principal component chart for multivariate statistical process control
    GM Oyeyemı
    TOJSAT 1 (2), 22-31 2011
    Citations: 9

  • An evaluation of savings culture among commercial motorcyclists in Nigeria: A case study
    GT Arosanyin, AT Olowosulu, HI Mobolaji
    Management Journal 15 (2), 229-249 2014
    Citations: 7

  • Comparison of bootstrap and jackknife methods of re-sampling in estimating population parameters
    GM Oyeyemi
    Global Journal of Pure and Applied Sciences 14 (2), 217-220 2008
    Citations: 7

  • Pak. J. Statist. 2018 Vol. 34 (4), 331-358 ON DEVELOPMENT OF FOUR-PARAMETERS EXPONENTIATED GENERALIZED EXPONENTIAL DISTRIBUTION
    A Bukoye, GM Oyeyemi
    Pak. J. Statist 34 (4), 331-358 2018
    Citations: 6

  • Performance of Generalized Autoregressive Conditional Heteroscedasticity (GARCH) Models in Modeling Volatility of Brent Crude Oil Price
    SD Gbolagade, GM Oyeyemi, AO Abidoye, TJ Adejumo, AI Okegbade
    Ilorin Journal of Science 9 (1), 20-32 2022
    Citations: 4

  • A new robust method for estimating linear regression model in the presence of outliers
    T Alanamu, GM Oyeyemi
    Pacific Journal of Science and Technology 19 (1), 125-132 2018
    Citations: 4

  • A note on the precision of stratified systematic sampling
    AO Kareem, IO Oshungade, GM Oyeyemi
    Open Journal of Statistics 5 (02), 104 2015
    Citations: 4

  • A note on the efficiency of geographic stratification
    AO Kareem, GM Oyeyemi, B Aiyelabegan Adijat
    International Journal of Mathematics and Statistics Invention 3 (4), 1-10 2015
    Citations: 4