Comparison of variance component estimation methods with an application on egg quality and weight

In this study, some important methods such as; ANOVA, Henderson III, ML, REML, MINQUE which are commonly used in literature to estimate variance components, are aimed to investigate comparatively for balanced and unbalanced data. In this context, the variance components related to egg weight and Haugh unit -describing the state of freshness or staleness of table eggs- are estimated with these methods. As a result of this study, with the unbalanced data for the estimation of variance components of Haugh unit, the method that estimated the effect of hen age with the highest rate is Henderson III (36.59%), the method with the lowest rate is ML (23.05%). To determine the influence of the hen age on the egg weight, the highest estimation is found by MINQUE (72,31%) and the lowest estimation is found by ML (%56,56). In the balanced data, for both Haugh units and egg weight, variance components estimates are found equal in four methods, but error ratio in ML method is found higher than other methods. It is expected that the research results will contribute to the statistical literature as well as the researchers in different areas in need of these methods.