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Comparison of Parametric and Nonparametric Item Response Techniques in Determining Differential Item Functioning in Polytomous Scale
T. Oguz Basokcu,
Tuncay Ogretmen
Issue:
Volume 3, Issue 2, March 2014
Pages:
31-38
Received:
31 December 2013
Published:
20 March 2014
Abstract: This study aims to compare parametric and nonparametric methods based on Item Response Theory in determining differential item functioning in polytomous scales. DIF analysis based on parametric IRT was conducted by using parameters comparison method. For nonparametric IRT analysis, DIF is determined by comparison of area indices pertaining to ICC obtained for reference and focal groups. The Comparisons were conducted on data sets from TIMSS 2011 8th Class students survey where data set pertaining to responses of students to "Attitudes Toward Mathematics" composing of samplings from Turkey and South Korea and it was determined if it incorporated DIF according to country and sex differences. It is observed that parametric and nonparametric methods produce generally similar results for DIF analysis in terms of countries. Nevertheless, DIF analysis results for country based sex groups differed according to techniques based on parametric and nonparametric IRT. Results of the study showed that items incorporating DIF differed as to preferred technique. This indicated importance of choosing the best technique in studies to detect whether scale items incorporates DIF or not.
Abstract: This study aims to compare parametric and nonparametric methods based on Item Response Theory in determining differential item functioning in polytomous scales. DIF analysis based on parametric IRT was conducted by using parameters comparison method. For nonparametric IRT analysis, DIF is determined by comparison of area indices pertaining to ICC o...
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Markov Chain Model and Its Application to Annual Rainfall Distribution for Crop Production
Abubakar Usman Yusuf,
Lawal Adamu,
Muhammed Abdullahi
Issue:
Volume 3, Issue 2, March 2014
Pages:
39-43
Received:
30 December 2013
Published:
20 March 2014
Abstract: A stochastic process with a first order dependence in discrete state and time is described as Markov chain. This principle was used to formulate a four state model for annual rainfall distribution in Minna with respect to crop production. The model is designed such that if given any of the four state in a given year, it is possible to determine quantitatively the probability of making transition to any other three states in the following year(s) and in the long-run. The model was used to study the data of annual rainfall in Minna. The results show that in the long run 14% of annual rainfall shall be low rainfall, 34% annual rainfall will be moderate rainfall also well spread, 47% of the annual rainfall shall be high rainfall and 5% of the annual rainfall shall be moderate rainfall not well spread respectively. The model provides some information about rainfall in relation to crops cultivation that could be used by the farmers and the government to plan strategy for high crop production in Minna and the immediate environment.
Abstract: A stochastic process with a first order dependence in discrete state and time is described as Markov chain. This principle was used to formulate a four state model for annual rainfall distribution in Minna with respect to crop production. The model is designed such that if given any of the four state in a given year, it is possible to determine qua...
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Direct and Indirect Effects in Dummy Variable Regression
Oyeka I. C. A.,
Nwankwo Chike H.
Issue:
Volume 3, Issue 2, March 2014
Pages:
44-48
Received:
3 December 2013
Published:
20 February 2014
Abstract: This paper proposes and develops the use of the non-cummulative dummy variables of 1’s and 0’s to represent levels of parent independent variables in dummy variable multiple regression models. The regression coefficients obtained using the proposed methods are easier to interprete and clearly understand than the use of the cummulatively coded ordinal dummy variables of 1’s and 0’s that could be used for the same purpose. The proposed method also enables the simultaneous estimation of the total, absolute or overall effect of a parent independent variable as well as its direct effect through its representative dummies and its indirect effect on a given independent variable through the mediation of other parent independent variables in the model was demonstrated. The use of these procedures was illustrated with an example.
Abstract: This paper proposes and develops the use of the non-cummulative dummy variables of 1’s and 0’s to represent levels of parent independent variables in dummy variable multiple regression models. The regression coefficients obtained using the proposed methods are easier to interprete and clearly understand than the use of the cummulatively coded ordin...
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Logit Models for Household Food Insecurity Classification
Abraham Yeyo Owino,
Leonard Kiboijana Atuhaire,
Ronald Wesonga,
Fabian Nabugoomu,
Elijah Muwanga-Zaake
Issue:
Volume 3, Issue 2, March 2014
Pages:
49-54
Received:
20 March 2014
Accepted:
22 April 2014
Published:
30 April 2014
Abstract: Micro-level measurement of food insecurity is a necessary approach towards a more feasible solution to the global problem for proper classification of households by food insecurity status. Measurement of food insecurity is a challenge because it is a multi-faceted latent and continuous phenomenon explained by a wide range of both quantitative and qualitative variables. In this paper, we examined the quantitative variables and applied exploratory factor analysis to identify which of them significantly influence household food insecurity. Logit models were then developed using the variables identified. Further, empirical data obtained from Tororo and Busia rural households in Uganda were used to fit the models. Four logit models based on four scenarios were developed and compared. The key findings pointed to the fact that if households were to be correctly analyzed and classified into the right food security category, a hybrid dependent variable that represents as many aspects of food insecurity as possible should be used. The model correctly classified 90 % of the combined households for two districts. However, when fitted for separate districts, it was established that 99% of households in Busia and 96% in Tororo district respectively, were found to be food insecure
Abstract: Micro-level measurement of food insecurity is a necessary approach towards a more feasible solution to the global problem for proper classification of households by food insecurity status. Measurement of food insecurity is a challenge because it is a multi-faceted latent and continuous phenomenon explained by a wide range of both quantitative and q...
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On Some Classical Properties of Doubly Truncated Mixture of Burr XII and Weibull Distributions
Muhammad Daniyal,
Muhammad Aleem,
Tahir Nawaz
Issue:
Volume 3, Issue 2, March 2014
Pages:
55-59
Received:
21 February 2014
Accepted:
29 April 2014
Published:
30 April 2014
Abstract: Limited work has been conducted on the doubly truncation for the mixture of different distributions. This paper is concerned with the doubly truncated mixture of Burr XII and Weibull distributions. In this paper, classical properties of the doubly truncated mixture of Burr XII and Weibull distributions have been derived. Cumulative distribution function, hazard rate, failure rate, inverse hazard function, odd function and the cumulative hazard function, rth moment about origin, moment generating function characteristic function, moments about origin and mean, mean and variance, measure of skewness and kurtosis have been discussed.
Abstract: Limited work has been conducted on the doubly truncation for the mixture of different distributions. This paper is concerned with the doubly truncated mixture of Burr XII and Weibull distributions. In this paper, classical properties of the doubly truncated mixture of Burr XII and Weibull distributions have been derived. Cumulative distribution fun...
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