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

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

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

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

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

Data analysis on physical and mechanical properties of cassava pellets

In this data article, laboratory experimental investigation results carried out at National Centre for Agricultural Mechanization(NCAM) on moisture content,machine speed,die diameter of the rig, and the outputs (hardness,durability,bulk density,and unit density of the pellets) at different levels of cassava pellets were observed. Analysis of variance using randomized complete block design with factorial was used to perform analysis for each of the outputs: hardness,durability,bulk density,and unit density of the pellets. A clear description one ach of these outputs was considered separately using tables and figures. It was observed that for all the output with the exception of unit density,their main factor effects as well as two and three ways interactions is significant at 5% level.This means that the hardness,bulk density and durability of cassava pellets respectively depend on the moisture content of the cassava dough,the machine speed,the die diameter of the extrusion rig and the combinations of these factors in pairs as well as the three altogether .Higher machine speeds produced more quality pellets at lower die diameters while lower machine speed is recommended for higher die diameter.Also the unit density depends on die diameter and the three-way interactiononly.Unit density of cassava pellets is neither affected by machine para- meters nor moisture content of the cassava dough.Moisture content of cassava dough,speed of the machine and die diameter of the extrusion rigare significant factors to be considered in pelletizing cassava to produce pellets.Increase in moisture content of cassava dough increase the quality of cassava pellets

A Note on the Minimax Distribution

We introduce a one parameter probability model bounded on (0, 1) support called One Parameter Minimax distribution which is a special case of both the Kumaraswamy distribution and Beta distribution. Its statistical properties are systematically explored; we provide explicit expressions for its moments, quantile function, reliability function and failure rate. The method of maximum likelihood estimation was used in estimating its parameter. The proposed model can be used to model data sets with increasing failure rate

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

Covid-19 #Takeresponsibility: A Multimodal Discourse Analysis of Select NCDC’s Online Public Health Advertising Campaign

This article examines the Nigerian Center for Disease Control’s (henceforth, NCDC) Covid-19 #TakeResponsibility online public health advertising campaign. This is with a view to exploring how the representational, interactive and compositional resources are realized in these advertising visuals as well as their communicative functions. Forty purposively selected data samples, which were subjected to qualitative analysis, are examined from a multimodal discourse analytical approach. The analysis reveals that the narrative, transactive, action, offer, and the frontal resources, among others, are realized in the adverts. These resources interactively perform the directive, informative, reinforcing, preventive, cautionary and collective functions. Thus, the representational, interactive and compositional resources deployed in the NCDC’s Covid-19 #TakeResponsibility online visuals discursively cohere as multimodal public health campaign strategies geared towards sensitizing the Nigerian populace on the safety guidelines to adhere to in containing the spread of Covid-19 in Nigeria