Degree of multicollinearity and variables involved in linear dependence in additive-dominant models

Pesquisa Agropecuária Brasileira

Juliana Petrini²  Raphael Antonio Prado Dias¹  Simone Fernanda Nedel Pertile²  Joanir Pereira Eler¹  José Bento Sterman Ferraz¹  Gerson Barreto Mourão² 

[1] ,Universidade de São Paulo Escola Superior de Agricultura Luiz de Queiroz Departamento de ZootecniaPiracicaba SP ,Brazil

关键词: Bos taurus x Bos indicus;    animal breeding;    beef cattle;    correlation matrix;    crossbreeding;    variance inflation factor;    Bos taurus x Bos indicus;    melhoramento animal;    bovino de corte;    matriz de correlação;    cruzamento;    fator de inflação da variância;   

DOI  :  10.1590/S0100-204X2012001200010

来源: SciELO

【 摘 要 】

The objective of this work was to assess the degree of multicollinearity and to identify the variables involved in linear dependence relations in additive-dominant models. Data of birth weight (n=141,567), yearling weight (n=58,124), and scrotal circumference (n=20,371) of Montana Tropical composite cattle were used. Diagnosis of multicollinearity was based on the variance inflation factor (VIF) and on the evaluation of the condition indexes and eigenvalues from the correlation matrix among explanatory variables. The first model studied (RM) included the fixed effect of dam age class at calving and the covariates associated to the direct and maternal additive and non-additive effects. The second model (R) included all the effects of the RM model except the maternal additive effects. Multicollinearity was detected in both models for all traits considered, with VIF values of 1.03 - 70.20 for RM and 1.03 - 60.70 for R. Collinearity increased with the increase of variables in the model and the decrease in the number of observations, and it was classified as weak, with condition index values between 10.00 and 26.77. In general, the variables associated with additive and non-additive effects were involved in multicollinearity, partially due to the natural connection between these covariables as fractions of the biological types in breed composition.

【 授权许可】

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