| 1 |
Author(s):
Okeke Ngozi Christy, Olanrewaju Samuel Olayemi, Zubair Mohammed Anono.
Page No : 1-10
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Heteroscedasticity and Multicollinearity Problems in Simultaneous Equation Model (SEM) Estimation: A Review of Methods and Applications.
Abstract
Multicollinearity, a situation where explanatory variables in a regression model are highly correlated, remains a fundamental challenge in statistical analysis, particularly when dealing with complex datasets. When multicollinearity occurs, it becomes difficult to isolate the individual effects of predictor variables, often leading to inflated standard errors, unstable parameter estimates, and reduced statistical power. Numerous authors have contributed significantly to the body of literature surrounding the detection, consequences, and mitigation of multicollinearity across various regression models, and in recent years, innovative approaches have emerged that aim to address this issue directly. This section provides an overview of these advancements, highlighting the progress made in linear regression modeling and emphasizing the need for similar innovations in the context of simultaneous equation models (SEMs). Another significant challenge in estimating Linear Regression Model is the presence of heteroscedasticity, where the variance of the error terms is not constant across observations (Chen & Wang, 2018). Heteroscedasticity violates one of the key assumptions of the OLS method, leading to inefficient and biased estimates of the regression parameters. To address this issue, heteroscedasticity-consistent estimators, such as Whites robust standard errors and the Generalized Method of Moments (GMM), have been developed (Pérez-Sánchez et al., 2021). These methods provide more reliable estimates in the presence of heteroscedasticity by accounting for the varying error variances. In SEMs, heteroscedasticity is particularly problematic because the error terms in different equations may have different variances, and these variances may be correlated with the explanatory variables. There is need to address this issue within SEMs framework
| 2 |
Author(s):
Olawuyi O. M., Isobeye G., Abegye S. Y. (Ph.D.).
Page No : 11-40
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Mathematical Analysis of Typhoid-HCV Co-Infection Transmission Dynamics.
Abstract
The World Health Organization had strategized a global eradication of hepatitis C virus (HCV) since 2016 because of its impact on global population. Its elimination has been prolonged because it was discovered that the diseases can co-exit with Typhoid fever and both illnesses contributing significantly to morbidity and long-term health complications. Therefore, a study was conducted using a compartmental model to explain the transmission dynamics of this co-infection leading to a non – linear deterministic equation. The basic reproduction number ( R_0) was obtained by next-generation method and the two criterions for stability conditions were computed.. The free equilibrium point was evluated and showed to be locally asymptotically stable when the threshold quantity is less than one. It was shown that both the analytical and numerical results agree with each others. Also, the results revealed that the susceptible population initially dominated but gradually declined as infection spread, while the recovered class steadily increased due to effective treatment and vaccination. Co-infection levels (A_C) remained low but persistent without control, confirming the synergistic effect of both pathogens.
| 3 |
Author(s):
Ernest Kwaku Ofosu, Samuel Kwesi Asiedu-Addo, Sylvester Frimpong, Dennis Offei Kwakye, Sulemana Karim, Daniel Kudjo Adiku, Gabina Susuoroka, Yahaya Mohammed Sherif-Deen, Thomas Mensah-Wonkyi, Alex Boadu.
Page No : 41-65
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Preservice Mathematics Teachers’ Perception on Computational Thinking as Problem-Solving Strategy in Teaching and Learning.
Abstract
Problem solving is a central goal of mathematics education and a key competency emphasized in Ghana’s basic school mathematics curriculum. However, many stakeholders are of the view that classroom practices often prioritize routine procedures rather than strategies that promote critical and analytical thinking. Computational thinking (CT), which involves cognitive processes such as decomposition, pattern recognition, abstraction, and algorithmic thinking, has increasingly been recognized as a powerful framework for structured problem solving that can enhance mathematical reasoning and learning. Despite its potential pedagogical value, the integration of CT, particularly in unplugged forms that do not require digital technologies, seems limited in mathematics teacher education programs, and little is known about preservice mathematics teachers’ perceptions of its role in mathematical problem solving.
| 4 |
Author(s):
Sohanur Rahman, M. U. Ahammad.
Page No : 66-82
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Optimizing Resource Allocation and Production Trend in Bangladeshi Rice Cultivation Using Linear Programming.
Abstract
Rice production is a cornerstone of food security and rural incomes in Bangladesh, but seasonal variation in rice production and resource constraints on agriculture are significant challenges to sustained growth of output. This study formulates an LP model to analyze the production trends and resource allocation pattern of three dominant rice cultivation seasons such as Aus, Aman and Boro in the region. The model combines important production resources, such as land, labor, fertilizer and irrigation water to determine the optimal allocation of these resources so that the total rice output can be maximized and a profit-maximum target for each farm could be achieved within limits of available resource supply. Season wise production, area, yield and input use data of the reference period (2018-23) were obtained following secondary sources mostly from Bangladesh Bureau of Statistics (BBS), BRRI (Bangladesh Rice Research Institute) and DAE (Department of Agricultural Extension). Descriptive trend analysis shows that, while Boro rice dominates due to higher productivity and irrigation used for this crop compared to Aus or Aman, the production of Aus and Aman is highly variable driven by rainfall and input constraints. The LP findings show that shifting land and resources to the water rice seasons with relatively higher yield return has a significant positive impact on gross margin without increasing total cropped area. The results emphasize the significance of better usage of resources including water (irrigation water saving), and labor to improve rice productivity. The developed optimization model represents a useful decision-support system for the policy makers and planners to support sustainable rice production and resource productivity in Bangladesh.
| 5 |
Author(s):
Moses Ayokunle Akanbi, Atinuke Bagbe.
Page No : 83-94
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Gender Variations in Care Supports Received by Senior Citizens in Ondo State, Nigeria.
Abstract
The study investigates gender variations in care supports received by senior citizens in Ondo state, Nigeria. Data was collected from sampled family care-givers (20-59 years) with senior citizens (50-99 years), who received care supports in Ondo state, Nigeria. A total sample size of 61 family care-givers participated in online questionnaire interviews at Okitipupa Local Government Area (LGA) of Ondo state. Frequency tables, cross-tabulation and binary logistics regression were used to analyze the data collected through online questionnaires. The results derived from the study are as follows: The different care supports received by male and female senior citizens include: financial; financial and medical; financial and multiple cares; medical care; multiple cares; physical care; physical and financial; physical, financial and medical cares; and physical, financial, medical and multiple cares. Obviously, the dominant care supports received by male and female senior citizens in the study are: financial (39.3%) and physical (32.8%). Furthermore, financial (p=0.000), medical (p=0.000), multiple (p=0.000) and physical (p=0.000) are significant care supports received by male and female senior citizens in the study. The study recommends that: medical and multiple cares must urgently become prioritized care supports to be packaged for male and female senior citizens in Ondo state and entire Nigerian societies.
| 6 |
Author(s):
Ekemini U. George, Matthew J. Iseh.
Page No : 95-104
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Demographic Analysis on Maternal Mortality Rate in Akwa Ibom State.
Abstract
This study examined maternal mortality in Akwa Ibom State – a state in the south-south region of Nigeria. Special attention was paid to a fundamental demographic factor, age, and a medical factor. Partitioning the population into age groups, it was realized that the age group with the highest mortality rate (42,105 out of every 100,000), is between 43 – 49, though it has the lowest number of pregnancies. In contrast, the age group with the highest number of pregnancies (1226), and the lowest maternal mortality rate (9,054, out of every 100,000) is between 25 – 30. Independence tests were carried out to ascertain, whether or not, mortality status depends on age group and delivery method. The results showed that while status was not affected by delivery method, it significantly depended on age group. This result was further seen in the binary logistic regression model fitted to the data, to determine the extent of the relationship between status and these factors. The model showed that age is a significant variable in determining mortality status, while delivery method is not. It is recommended that the age limit at first marriage for young girls should be increased, in a bid to stem maternal mortality due to complications, within the age group (10-19). Sensitization campaigns should be mounted, to eliminate, or at least reduce the barriers to safe abortion, as this will reduce the risk of maternal mortality within higher age groups.
