Modelling Negative Binomial as a substitute model to Poisson for raters agreement on ordinal scales with sparse data

The Poisson distribution has been widely used for modelling rater agreement using loglinear models. Mostly in all life or social science researches, subjects are being classified into categories by rater, interviewers or observers and most of these tables indicate that the cell counts are mixtures of either too big values and two small values or zeroes which are sparse data. We refer to sparse as a situation when a large number of cell frequencies are very small. For these kinds of tables, there are tendencies for overdispersion in which the variance of the outcome or response exceeds the nominal variance, that is, when the response is greater than it should be under the given model or the true variance is bigger than the mean. In these types of situations assuming Poisson models means we are imposing the mean-variance equality restriction on the estimation. This implies that we will effectively be requiring the variance to be less than it really is, and also, as a result, we will underestimate the true variability in the data. Lastly, this will lead us to underestimating the standard errors, and so to overestimating the degree of precision in the coefficients. The Negative Binomial, which has a variance function, would be better for modelling rater agreement with sparse data in the table in order to allow the spread of the observations or counts. We observed that assuming Negative Binomial as the underline sampling plan is better for modelling rater agreement when there are sparse data in a limited number of example

Conditional symmetry model as a better alternative to Symmetry Model for rater agreement measure

In almost all life or social science researches, subjects are classified into categories by raters, interviewers or observers. Many approaches have been proposed by various authors for analyzing the data or the results obtained from these raters. Symmetry and conditional symmetry models are models designed for square tables like the one arising from the raters results. Conditional symmetry model which possessed an extra parameter for the off-diagonal cells is a special case to symmetry. In this research work, we examined the effect of the extra parameter introduced by conditional symmetry model over that of symmetry on structure of agreement as well as their fittings. Generalized linear model (GLM) approach was used to model the loglinear model forms of these models with empirical examples. We observed that conditional symmetry based on it extra parameter gave a tremendous improvement to the significant level of the test statistics over that of its symmetry model counterpart, hence conditional symmetry model is better for raters agreement modelling which require symmetric table

Crop protection strategies for major diseases of cocoa, coffee and cashew in Nigeria

A great percentage of people in the developing countries are engaged in agriculture, but the yields of their produce are low due to diseases that plague their crops. In Nigeria, crop protection measures that are cheap, simple, cost-effective and sustainable are desirable to combat Phytophthora pod rot (black pod) and cocoa swollen shoot virus diseases of cocoa, coffee leaf rust and coffee berry diseases, inflorescence blight disease of cashew in order to make farming profitable and sustainable. Disease control strategies include the use of resistant cultivars, chemicals, biological, botanicals, cultural, physical controls and application of biotechnology, each of which is discussed in this paper.African Journal of Biotechnology Vol. 4 (2), pp. 143-150, 200

The impact of human capital development in employment generation in Nigeria

A major development issue in Nigeria is unemployment, despite a plethora of economic policies to guide labour absorption and utilisation in the country. Some major reasons  for this unemployment challenges have been hinged on the level of human capital  development as well as other socio-economic issues. Using the Auto Regressive  Distributed Lag (ARDL) approach, a quantitative analysis of the effect human capital in stimulating employment or otherwise was assessed in Nigeria for the period  1970-2014. It was discovered that the level of human capital was not sufficient to stimulate employment or reduce unemployment in Nigeria. Besides, it was discovered that population growth is really not the challenge for employment in Nigeria especially if human capital can be harnessed productively, and channelled towards viable and rewarding sectors of the economyKeywords: “Population”, “Employment”, “Education”, “Capital

A review of agreement measure as a subset of association measure between raters

Agreement can be regarded as a special case of association and not the other way round. Virtually in all life or social science researches, subjects are being classified into categories by raters, interviewers or observers and both association and agreement measures can be obtained from the results of this researchers. The distinction between association and agreement for a given data is that, for two responses to be perfectly associated we require that we can predict the category of one response from the category of the other response, while for two response to agree, they must fall into the identical category. Which hence mean, once there is agreement between the two responses, association has already exist, however, strong association may exist between the two responses without any strong agreement. Many approaches have been proposed by various authors for measuring each of these measures. In this work, we present some up till date development on these measures statistics

Post-harvest technology change in cassava processing: a choice paradigm

Open Access Article; Available online: 27 Jan 2020This study employed a choice model to examine the factors influencing the choice of post-harvest technologies in cassava starch processing, using a sample of five hundred and seventy (570) processors in the forest and guinea savanna zones of Nigeria. In addition, the profitability of various post-harvest technologies in the study area was assessed using the budgetary technique while the impact of improved post-harvest technology on processors’ revenue and output was analysed using the average treatment effect model. Sex of the processor, processing experience, income, and cost of post-harvest technology, the capacity of post-harvest technology and access to credit amongst others significantly influence the choice of post-harvest technologies. Although the use of improved post-harvest technology comes with a high cost, the net income from its use was higher than the other types of post-harvest technologies, suggesting that the use of improved techniques was more beneficial and profitable. In addition, using improved post-harvest technology had a positive and significant effect on output and income. These findings shows that investment in improved post-harvest technologies by cassava starch processors and other stakeholders would increase income, thus, improving welfare

Incidence of aflatoxins, fumonisins, trichothecenes and ochratoxins in Nigerian foods and possible intervention strategies

Mycotoxins are toxic secondary metabolites produced by some species of fungi. Aflatoxins, fumonisins, trichothecenes and ochratoxins are the common mycotoxins in Nigeria. Aflatoxin is the most frequently reported in literatures, with trichothecenes being the least, they cause yield loss to farmers as well as constituting major health risk to humans. The occurrence of mycotoxins in food is a serious problem that Nigeria is facing presently, as it continues to pose threat to feed and food safety of animals and humans. There is the need to seek for approaches that would lead to reduction in their toxicity. The practice of good sanitary measures right from the farm to storage, creation of awareness campaign to indicate the toxic effects associated with mycotoxin poisonings in humans and livestock, and proper evaluation of food crops for its presence can go a long way in achieving the target reduction in incidence of mycotoxins in Nigeria

Cost-benefit analysis of replacing maize with rice husk supplemented with grindazyme, nutrsea xyla or roxazyme g enzyme supplementation in the diet of Arbor Acres broilers

The experiment was carried out to investigate the cost-­‐benefit of replacing maize with rice husk supplemented with enzymes in the diet of arbor acres broilers. The experimental design was a 2×4 factorial combination of two dietary level of rice husk (0 or 25%) with four levels of different enzymes 0E (without enzyme 0ppm), 100E (100ppm of Nutrase xyla), 150E (150 ppm of Roxazyme G), or 350E (350ppm of Grindazyme). Rice husk was added at the expense of maize in the control diet and each experimental diet was tested during a 56-­‐day feeding trial in triplicate. One hundred and ninety-­‐two (192) one-­‐day old unsexed Arbor acres chicks were used in the trial. Each of these was undertaken in the presence of no enzyme 0E (0ppm) or with different types of commercial enzymes at recommended level, which are 100E (100ppm of Nutrase xyla), 150E (150ppm of Roxazyme G), and 350E (350ppm of Grindazyme). Cost of each ingredient was used to calculate the total cost; there were reductions in the cost of raising 1Kg of Arbor acre broiler on supplementation of the rice husk diets with commercial enzymes. The 25% replacement of maize with rice husk supplemented with commercial enzymes has no detrimental effect on the performance of the birds; rather the saving cost was associated with improved weight gain. The inclusion of rice husk supplemented with any of the enzymes in the diets reduced the cost of producing broilers and hence increased profit