Evaluation of Simultaneous Equation Techniques in the Presence of Misspecification Error: A Monte Carlo Approach

One  of  the  assumptions  of  Classical  Linear  Regression  Model (CLRMA),  is  that  the  regression  model be  ‘correctly’   specified.  If  the  model  is  not  ‘correctly’  specified,  the  problem  of  model  misspecification  error arises. The objective of the study is to know the performances of the estimator and also the estimator that is greatly affected by misspecification error due to omission of relevant explanatory variable.  Four simultaneous equation techniques (OLS, 2SLS, 3SLS, LIML) were applied to a two-equation model and investigated on their performances when plagued with the problem of misspecification error. A Monte Carlo method simulation method was employed to investigate the effect of these estimators due to misspecification of the model. The findings revealed that the estimates obtained by 2SLS and 3SLS are similar and variances by all the estimates reduced consistently as the sample size increases. The study had revealed that 2 3 SLS performed best using average of parameter criterion while OLS generated the least variances. LIML is mostly affected by misspecification. Keywords: Monte Carlo, Misspecification error, Simultaneous equation

Maximum Likelihood Estimation of the Kumaraswamy Exponential Distribution with Applications

The Kumaraswamy exponential distribution, a generalization of the exponential, is developed as a model for problems in environmental studies, survival analysis and reliability. The estimation of parameters is approached by maximum likelihood and the observed information matrix is derived. The proposed models are applied to three real data sets

Nutrient composition and suitability of four commonly used local complementary foods in Akwa Ibom State, Nigeria

Adequate nutrition is important during infancy and childhood where a short period of malnutrition has long lasting effects on growth, development and health in the adult life. The period from six months to two years constitutes a critical window of opportunity for promoting optimal growth, health and development, while insufficient quantity and quality of complementary foods (CFs), poor feeding practice and high rate of infection have a detrimental impact on growth in these important years. This study was designed to evaluate the nutrient composition and suitability of four commonly used complementary foods in two Local Government Areas (LGAs) of Akwa Ibom State, Nigeria. A descriptive cross-sectional survey involving women with children aged 6-24 months old was carried out in two randomly selected LGAs to identify the commonly used CFs. A total of 300 consenting mothers (150/LGA) aged 18 to 60 years presenting their children for immunisation in the two LGAs were respondents. A pretested, semi-structured questionnaire was used to obtain information on sociodemographic characteristics, knowledge on breastfeeding, complementary feeding practice, and types of CFs used from the respondents. Standardised samples of the four most commonly used CFs were prepared and analysed for nutrient and anti-nutrient composition using standard AOAC methods of analyses. Data were analysed using descriptive statistics and Chi square test, with level of significance set at p = 0.05. Two types of unripe banana porridge, one mashed bean porridge, and mixed cereal pap with crayfish and ‘turn brown’ (soybean flour, groundnut and crayfish) were the four most commonly used CFs. One hundred grams portion of the CFs contained between 2.52 - 6.70 g crude protein, 1.26 - 7.23 g crude lipid, 8.16 - 13.97 g carbohydrates and yielded up to 415.57 kcal of energy. The mineral content ranged between 31.58 - 230.40 mg potassium, 46.78 - 184.68 mg calcium, 55.23 - 120.93 mg phosphorus, 10.37 - 23.26 mg iron, 7.53 - 18.53 mg of zinc / 100g portion. The four complementary foods were nutritionally adequate and were low in anti-nutrients (oxalates, phytates, trypsin inhibitors, saponins and tannins), hence there is little risk of malabsorption of available nutrients. Utilization of unripe banana and mixed cereals with turn brown for infants provides cheap CFs with adequate energy and nutrients, and promotes biodiversity.Key words: Nutrients, Complementary foods, Banana, Cereal, Beans

HCME: An Environment-Friendly I.C. Engine Fuel

The study revealed that Hura crepitans oil is a good candidate for Hura crepitans methyl ester (HCME) production. Two steps (esterification and transesterification) production stages influenced the high yield of HCME. Three possible experimental runs were performed in each step, the best of the three conditions were 1.45 (% v/v) for H2SO4 conc., 5:1 for methanol/oil molar ratio, 40 min for reaction time which gave 1.06 % for FFA in the first step, in the second step, 92.70 %(w/w) of HCME was obtained at 0.55% KOH, 5:1 methanol/oil molar ratio, 60 oC temperature and 30 min reaction time. The produced HCME had fuel properties which satisfied both ASTME D6751 and EN 1424 standards. The fatty acid profile of the HCME revealed the dominant fatty acids were linoleic (64.50%), oleic (17.54%) and palmitic (12.70%). Exhaust emissions from an internal combustion (I.C.) engine revealed that there is 60% decreased in CO, 58% decreased in NOx, 60% decreased in HC, 39% decrease in smoke opacity and 42% decreased in BSFC at B20, respectively. Flue gas temperature increased by 12% at B20, 45% increased in BTE at B50 when compared to pure diesel (AGO). Hence, it can be concluded that B20 (20% HCME + 80% AGO) will provides the best emission reduction at the lowest cost

Assessing the Flexibility of the Exponentiated Generalized Exponential Distribution

A three parameter probability model which serves as a generalization of the Exponential distribution was studied. The new model is named Exponentiated Generalized Exponential (EGE) distribution. The shape of the model could be increasing, decreasing or unimodal (depending on the value of the parameters). Explicit expressions are provided for the moments and generating functions, reliability function and failure rate. The method of maximum likelihood estimation (MLE) was proposed for the estimation of the parameters. An application to two real data sets was provided in order to assess the flexibility of the proposed model over some models in the literature

Analysis of Income Diversification Strategies among Farm Households in Oyo State

Diversification of income sources is considered as a desirable option to augments income among small scale farmers. This study evaluates the income diversification among farm households in Oyo State of Nigeria. A multi-stage sampling technique was used to select 280 rural households. The data collected were analysed using diversity index and Tobit regression analysis. The results showed that all the respondents participated in arable farming and this accounts for 28.29 percent of the total income. 57.85 percent participated in tree crop income and this accounts for 11.95 percent of the total income, 60.36 percent of the households engaged in non-farm income and it accounts for 19.93 percent of the total income. The results of Tobit regression showed that education, household size, access to credit and extension contact were the factors increasing income diversification among the rural households in the study area. The study revealed that agriculture remains the major source of income among the respondents. Therefore, the study recommends improvement of agricultural activities through the distribution of agricultural inputs such as improved seeds, fertilizers and better extension services delivery in order to boost agricultural production. Keywords: Income diversification, Diversity index, Rural Household, Tobit regression

Bootstrap Approach for Estimating Seemingly Unrelated Regressions with Varying Degrees of Autocorrelated Disturbances

The Seemingly Unrelated Regressions (SUR) model proposed in 1962 by Arnold Zellner has gained a wide acceptability and its practical use is enormous. In this research, two methods of estimation techniques were examined in the presence of varying degrees of first order Autoregressive [AR(1)] coefficients in the error terms of the model. Data was simulated using bootstrapping approach for sample sizes of 20, 50, 100, 500 and 1000.  Performances of Ordinary Least Squares (OLS) and Generalized Least Squares (GLS) estimators were examined under a definite form of the variance-covariance matrix used for estimation in all the sample sizes considered. The results revealed that the GLS estimator was efficient both in small and large sample sizes. Comparative performances of the estimators were studied with 0.3 and 0.5 as assumed coefficients of AR(1) in the first and second regressions and these coefficients were further interchanged for each regression equation, it was deduced that standard errors of the parameters decreased with increase in the coefficients of AR(1) for both estimators with the SUR estimator performing better as sample size increased. Examining the performances of the SUR estimator with varying degrees of AR(1) using Mean Square Error (MSE), the SUR estimator performed better with autocorrelation coefficient of 0.3 than that of 0.5 in both regression equations with best MSE obtained to be 0.8185 using $\rho = 0.3$ in the second regression equation for sample size of 50

Challenges of Car Pack Design in Nigeria

Problems of parking space in urban towns and in all places of large congregation is becoming a common issue around the world. Over the years engineers and architects have come up with a lot of solutions finding a way to create more parking spaces within minimum size of land by the design and construction of multi-storey car parks. This is line with the trend in modern cities all over the world of developing high-rise buildings as to overcome the challenges of urban over population, for optimal use of scarce land resources, as status symbol, etc. Standing on the advances made so far and the frequent problematics verified on existing multi-storey car parks, this research presents the design of a multi-storey car park for the mitigation of traffic challenges in public areas using Canaan land, Ota Nigeria as a case study. Canaan land, the seat of Faith Tabernacle in Ota, Ogun State of Nigeria is used as a case study because of the amount of vehicles that compete for parking space on Sundays or on other days of events. The research consist of the creation of the architectural drawings of the multi-storey car park with AutoCAD drafting and the modelling, structural analysis and design using the software Orion R16. The structural analysis and design were challenging but good results were obtained, approach for more innovative multi-storey car park identifie

Estimation of Garch Models for Nigerian Exchange Rates Under Non-Gaussian Innovations

Financial series often displays evidence of leptokurticity and in that case, the empirical distribution often fails normality.  GARCH models were initially based on normality assumption but estimated model based on this assumption cannot capture all the degree of leptokurticity in the return series. In this paper, we applied variants of GARCH models under non-normal innovations-t-distribution and Generalized Error Distribution (GED) on selected Nigeria exchange rates. The Berndt, Hall, Hall, Hausman (BHHH) numerical derivatives applied in the estimation of models converged faster and the time varied significantly across models. Asymmetric GARCH model with t-distribution (GARCH-t) was selected in most of the cases whereas for Nigeria-US Dollar exchange rate, GARCH-GED was specified. Both distributions showed evidence of leptokurticity in Naira exchange rate return series. The result is of practical importance to practitioners. Key Words: GARCH, Exchange rate, Model specification, Non-Gaussian distribution.

Effects of Wheat and Fish Trade Restriction Policies on Households’ Vulnerability to Poverty in Nigeria

Against the expected trade liberalization policies as enunciated under the World Trade Organization (WTO) agreement, Nigeria currently uses trade restriction policies through tariffs and quotas to protect local producers and ensure self-sufficiency in staple food especially wheat and fish, which constitute 56% of annual food import. However, the general equilibrium effects of restrictive policy instruments are yet to be fully understood especially for the poor and the vulnerable. Living Standard (HNLSS) survey data for 2009/2010 and the NISER’s 2011 Social Accounting Matrix (SAM) were used. An 80% wheat and 50% fish tariff increase as currently implemented in Nigeria were used for the simulations. Data were analyzed using computable general equilibrium (CGE) technique and Vulnerability To Poverty (VTP) measure. Prior to policy simulations, vulnerable rural and urban households in NW had the highest observed poverty (68.2% and 71.2%) while, while the rural and urban households in the south-south zone had the least (53.0% and 45.5%) respectively. The expected poverty was highest in simulation three across vulnerable and non-vulnerable households. Consequently, the ratio of expected to observed poverty indicates that vulnerable rural and urban households have the highest likelihood of sinking deeper into poverty particularly with the combined policies in simulation three. It is therefore recommended that government should strengthen domestic production of food import substitutes backed with strong value addition. Keywords:Computable general equilibrium, Per-capita consumption expenditure, Social accounting matrix, Trade restrictions, Vulnerability to poverty DOI: 10.7176/JPID/50-06 Publication date:June 30th 201