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Full-Text Articles in Engineering

Contextual Effects In Modeling For Small Domain Estimation, Mohammad-Reza Namazi-Rad, David G. Steel Jan 2011

Contextual Effects In Modeling For Small Domain Estimation, Mohammad-Reza Namazi-Rad, David G. Steel

SMART Infrastructure Facility - Papers

Many different Small Area Estimation (SAE) methods have been proposed to overcome the challenge of findingreliable estimates for small domains. Often, the required data for various research purposes are available at differentlevels of aggregation. Based on the available data, individual-level or aggregated-level models are used in SAE.However, parameter estimates obtained from individual and aggregated level analysis may be different, in practice.This may happen due to some substantial contextual or area-level effects in the covariates which may be misspecifiedin individual-level analysis. If small area models are going to be interpretable in practice, possible contextualeffects should be included. Ignoring these effects leads …


Modeling Of Crossbred Cattle Growth, Comparison Between Cubic And Piecewise Random Regression Models, H R. Mirzaei, Wayne S. Pitchford, Arunas P. Verbyla Jan 2011

Modeling Of Crossbred Cattle Growth, Comparison Between Cubic And Piecewise Random Regression Models, H R. Mirzaei, Wayne S. Pitchford, Arunas P. Verbyla

Faculty of Engineering and Information Sciences - Papers: Part A

Two analyses, cubic and piecewise random regression, were conducted to model growth of crossbred cattle from birth to about two years of age, investigating the ability of a piecewise procedure to fit growth traits without the complications of the cubic model. During a four-year period (1994-1997) of the Australian "Southern Crossbreeding Project", mature Hereford cows (N = 581) were mated to 97 sires of Angus, Belgian Blue, Hereford, Jersey, Limousin, South Devon, and Wagyu breeds, resulting in 1141 steers and heifers born over four years. Data included 13 (for steers) and eight (for heifers) live body weight measurements, made approximately …