Simplified Freeman-Tukey test statistics for testing probabilities in contingency tables

This paper presents the simplified version of the Freeman-Tukey test statistic for testing hypothesis about multinomial probabilities in one, two and multidimensional contingency tables that does not require calculating the expected cell frequencies before test of significance. The simplified method established new criteria of collapsing cells whose frequency are less than 5. Illustrated examples compared favourably the new method with Pearson, Neyman and Likelihood ratio chi- squared statistics. Apart from being faster, the simplified version provides more accurate result since the problem of figure approximation is reduced. Keywords: Freeman-Tukey statistic, dimension, contingency table, multinomial probabilities, expected cell frequencie

THE NIGERIAN AGRICULTURE AND POVERTY INCIDENCE: THE NEED FOR PRIVATE SECTOR EMPOWERMENT

Poverty in Nigeria is concentrated in rural areas. Low resource or resource-poor farmers characterized by preponderance of small farm units, fragile soils, rain-dependent, minimum inputs and poor yield dominate the agricultural sector. The incidence of poverty is highest among households in which the head is engaged in agriculture as the main source of income. Agricultural growth is therefore important to the eradication of extreme poverty and hunger in Nigeria. Conscious policy efforts by government towards poverty alleviation began during the SAP era. Some companies like Shell and certain State Governments have shown real interest in alleviating poverty through their agricultural programmes and policy statements. Nigeria’s current vision for agricultural development is expressed in the National Economic Empowerment and Development Strategy (NEEDS), the New Agricultural Policy (NAP), and the Rural Sector Development Strategy (RSDS). This paper posits that provision of electricity, potable water, health centres and formal schools will facilitate the sustainability of any impact of poverty alleviation programmes in Nigeria. Encouraging community development projects evolved by the communities themselves will minimize poverty incidence. Increasing the access of the poor to land and other productive resources will reduce poverty and generate employment. Development of infrastructural facilities in the rural areas has the two pronged approach of reducing poverty and developing the rural areas. Encouraging processing through adequate incentives to SMEs will also further empower the private sector.Farm Management, Food Security and Poverty,

A comparative study of the performances of some estimators of linear model with fixed and stochastic regressors

In linear regression model, regressors are assumed fixed in repeated sampling. This assumption is not always satisfied especially in business, economics and social sciences. Consequently in this paper, effort is made to compare the performances of some estimators of linear model with autocorrelated error terms when normally distributed regressors are fixed (non – stochastic) with when they are stochastic. The estimators are the ordinary least square (OLS) estimator and four feasible generalized least estimators which are Cochrane Orcutt (CORC), Hidreth – Lu (HILU), Maximum Likelihood (ML), Maximum Likelihood Grid (MLGD) estimator. These estimators are compared using the finite properties of estimators' criteria namely; sum of biases, sum of variances and sum of the mean squared error of the estimated parameter of the model at different levels of autocorrelation and sample size through Monte – Carlo studies. Results show that at each level of autocorrelation the estimated value of the criteria with stochastic regressor are much lesser than that of the fixed regressor for all the estimators except CORC when the sample size is small (n=20) and the level of autocorrelation is very high . More comparatively, it is observed that the same estimator(s) that is more efficient with fixed regressors is also more efficient with stochastic regressors except when the sample size is large (n = 80) and the level of autocorrelation is either low or high . At these instances, the CORC / HILU estimator is more efficient with fixed regressors while the ML / MLGD estimator is more efficient with stochastic regressors Keywords: Fixed Regressors, Stochastic Regressors, Linear Model, Autocorrelated error, OLS estimator, Feasible GLS estimatorsGlobal Journal of Pure and Applied Sciences Vol. 14 (3) 2008: pp. 363-37

Prediction Using Estimators of Linear Regression Model with Aurocorrelated Error Terms and Correlated Stochastic Uniform Regressors

Prediction remains one of the fundamental reasons for regression analysis. However, the Classical Linear Regression Model is formulated under some assumptions which are not always satisfied especially in business, economic and social sciences leading to the development of many estimators. This work, therefore, attempts to examine the performances of the Ordinary Least Square estimator (OLS), Cochrane-Orcutt estimator (COR), Maximum Likelihood estimator (ML) and the estimators based on Principal Component analysis (PC) in prediction of linear regression model under the violations of assumption of non – stochastic regressors, independent regressors and error terms. With stochastic uniform variables as regressors, Monte - Carlo experiments were conducted over the levels of autocorrelation, correlation between regressors (multicollinearity -) and sample sizes, and best estimators for prediction purposes are identified using the goodness of fit statistics of the estimators. Results show that the performances of COR and ML at each level of multicollinearity over the levels of autocorrelation have a convex – like pattern while that of OLS, PR1 and PR2 are concave – like. Also, as the level of multicollinearity increases the estimators especially the COR and ML estimators perform much better at all the levels of autocorrelation. Furthermore, results show that except when the sample size is small (n=10), the performances of the COR and ML estimators are generally best and almost the same, even though at low level of autocorrelation the PC estimator either performs better than or competes with the best estimator when  and . When the sample size is small (n =10), the COR estimator is best except when the autocorrelation level is low and  or. At these instances, the PR2 estimator is best. Moreover, at low level of autocorrelation in all the sample sizes, the OLS estimator competes with the best estimator in all the levels of multicollinearity. .Keywords: Prediction, Estimators, Linear Regression Model, Autocorrelation, Multicollinearity                     

POTABILITY AND IRRIGATION POTENTIAL OF GROUNDWATER SOURCES AT THE FEDERAL UNIVERSITY OF AGRICULTURE, ABEOKUTA, NIGERIA

Groundwater is an important source of freshwater and its quality determines it’s potential for domestic and agricultural use. Water samples from ten boreholes located within the Federal University of Agriculture Abeokuta, Nigeria were collected and analysed for physico-chemical and bacteriological properties, cations and metals using standard procedures. Results were compared with the regulatory standards while water quality index (WQI) method was used to classify the water potability. Potential of groundwater for irrigation was investigated using appropriate indices. The range of values for the measured parameters include: pH: 6.9 – 7.82; electrical conductivity(EC): 127 – 650 μS/cm; total dissolved solids (TDS): 58 to 284 mg/L; magnesium (Mg2+): 10 - 61 mg/L; nitrates (NO3-): 0.01 – 1.38 mg/L; iron (Fe): 0.02 – 0.05 mg/L; biological oxygen demand (BOD): 0.1 – 2.83 mg/L and total coliform: ND - 28×10cfu/mL. Majority of the water quality parameters fell within regulatory limits with the exception of magnesium and total coliforms. Escherichia coli, an indicator of faecal contamination was also absent in the water samples. On the average, groundwater within the study area has a WQI = 46.3 and can be classified to be of good quality for domestic use.  Sodium absorption ratio (SAR) was less than 10% and Magnesium adsorption ratio (MAR) was less 50 %, and are therefore classified as of excellent quality for irrigation purpose. Soluble sodium percentage (SSP) values range between 11.1 and 51 %. All samples were found to be good or fair for irrigation purpose with no harmful effects to the soil.     &nbsp

Management Strategies of Perceived Risk Associated with Moringa Products by Consumers in Ilorin Metropolis, Kwara State, Nigeria

This study focused on examining the management strategies of perceived risk associated with Moringa products by consumers in Ilorin metropolis with view to rank the perceived risk associated with Moringa product; assess the different strategies employed by consumers to manage or cope with the risk and to examine socio-economic determinants of consumers’ consumption behaviour in relation to the perceived risk. Primary data were collected with the aid of a well structured questionnaire from 116 sampled respondents in the study area. The data were analysed using descriptive statistics and the Tobit regression model. The result shows that majority of the consumers consume Moringa powder while none of them consume Moringa oil. It was also discovered that most of the respondents do nothing about the risk associated with Moringa consumption, while some of them reduce the quantity consumed per dose or frequency consumption. Awareness of risk and consumption of Moringa powder were found to have significant effect on consumer attitude towards the perceived risk at (p<0.1). The study therefore recommends the need for more clinical trials that will ascertain the long term health implication of Moringa products consumption and the need for marketing agencies to take advantage of the relative ambivalence to Moringa consumption for more advertorial and promotional campaigns

Bilateral multicystic dysplastic kidneys: Case report

Multicystic dysplastic kidney (MCDK) is a congenital, non-heritable maldevelopment in which the renal cortex is replaced by numerous cysts of varying sizes. Typically, MCDK is a unilateral disorder in 76% of cases and bilateral in 24%. The latter is incompatible with life. We present the case of a male child with bilateral MCDK who was followed up with ultrasound scan (USS) from 22nd week of intrauterine life till death on the 19th day after delivery. Serial antenatal USS revealed oligohydramnios and both kidneys showed multiple cysts which appeared to be communicating. Postnatal USS however, revealed multiple sub-cortical thin walled cysts of varying sizes which apparently appeared to be communicating. A diagnosis of bilateral MCDK was made and was confirmed at autopsy

Robust-M new two-parameter estimator for linear regression models: Simulations and applications

In the presence of multicollinearity and outliers, the ordinary least squares estimator remains inconsistent and unreliable. Several estimators have been proposed that can co-handle the problems of multicollinearity and outliers simultaneously. However, there is still a need to explore some other robust methods when the two anomalies appear in the linear regression model and recommend it to end users of statistics. Therefore, this study proposed Robust-M New Two Parameter (RNTP) and examined its performance over some already existing ones in the presence of multicollinearity and outliers in the x-direction. The theoretical expression under some conditions was established to showcase the new estimator's superiority. A simulation study was carried out alongside some factors to show that the RNTP is better than all other estimators considered in the study. The simulation study results revealed that RNTP outperformed other estimators in the study using the minimum MSE as the criterion. Likewise, real-life data was applied to affirm this claim

Modulation of ex-vivo uterine contraction by the methanol leaf extract of Alchornea laxiflora Benth. (Euphorbiaceae) and preliminary spectrometric identification of associated secondary metabolites

Background: The leaves of Alchornea laxiflora are traditionally used in the south of Nigeria to prevent preterm births.   Aim: This study was designed to investigate the activity of A. laxiflora on uterine contractility.   Setting: The leaves of the plant were collected from forests in Egor, Benin City, Nigeria.   Methods: The leaves were cleaned and extracted in methanol. The extract (0.005 mg/mL–3.5 mg/mL) was tested on spontaneous uterine contraction and on oxytocin-induced contraction in normal and Ca2+-free media. The plant extract (0.0035 mg/mL, 0.035 mg/mL, 0.35 mg/mL and 3.5 mg/mL) was tested on high KCl-induced uterine contractions (80 mM). The plant extract (3.5 mg/mL) was also studied in the presence of amiodarone and glibenclamide in separate experiments. Mass spectrometric analysis was additionally performed on the plant extract in order to identify significant secondary metabolites that may have contributed to the activity of the plant.   Results: The plant extract inhibited spontaneous, oxytocin and high KCl-induced uterine contractions and also significantly inhibited (p < 0.01) oxytocin-induced uterine contraction in Ca2+-free medium. The plant extract significantly inhibited (p < 0.01 and p < 0.05) oxytocin’s amplitude in the presence of amiodarone and glibenclamide, respectively. Secondary metabolites belonging to classes of fatty acids, glycols, terpenes, flavonoid glycosides and porphyrins were identified.   Conclusion: Alchornea laxiflora inhibited mouse uterine contractility possibly through interaction with potassium and calcium channels. Of the known metabolites identified, 3-deoxy-arabino-hept-2-ulosonic acid, 17-hydroxyingenol and phaeophorbide-a methyl inhibit uterine contractility and may contribute to the activity of A. laxiflora in utero