Department of Mathematical Science;
Abubakar Tafawa Balewa University;
Bauchi;
Nigeria;
Federal College of Education (Tech.);
Gombe;
Gombe State;
Nigeria;
Department of Mathematics and Statistics;
University of Maiduguri;
Maiduguri;
Nigeria;
Heteroscedasticity; Kurtosis; Model; Efficiency; Outliers; Unconditional; Variance; Volatility;