Please use this identifier to cite or link to this item: http://repositorio.ufla.br/jspui/handle/1/38946
Title: Ajuste de modelos de platô de resposta via regressão isotônica
Other Titles: Response plateau models fitting via isotonic regression
Keywords: Isotonização
Modelos segmentados
Modelos não lineares
Simulação Monte Carlo
Isotonization
Segmented models
Nonlinear models
Monte Carlo simulations
Issue Date: Feb-2012
Publisher: Universidade Federal de Santa Maria
Citation: GONÇALVES, R. P. et al. Ajuste de modelos de platô de resposta via regressão isotônica. Ciência Rural, Santa Maria, v. 42, n. 2, p. 354-359, fev. 2012.
Abstract: Within the nutritional context, the supplementation of microminerals in bird food is often made in quantities exceeding those required in the attempt to ensure the proper performance of the animals. The experiments of type dosage x response are very common in the determination of levels of nutrients in optimal food balance and include the use of regression models to achieve this objective. Nevertheless, the regression analysis routine, generally, uses a priori information about a possible relationship between the response variable. The isotonic regression is a method of estimation by least squares that generates estimates which preserves data ordering. In the theory of isotonic regression this information is essential and it is expected to increase fitting efficiency. The objective of this work was to use an isotonic regression methodology, as an alternative way of analyzing data of Zn deposition in tibia of male birds of Hubbard lineage. We considered the models of plateau response of polynomial quadratic and linear exponential forms. In addition to these models, we also proposed the fitting of a logarithmic model to the data and the efficiency of the methodology was evaluated by Monte Carlo simulations, considering different scenarios for the parametric values. The isotonization of the data yielded an improvement in all the fitting quality parameters evaluated. Among the models used, the logarithmic presented estimates of the parameters more consistent with the values reported in literature.
URI: http://repositorio.ufla.br/jspui/handle/1/38946
Appears in Collections:DEX - Artigos publicados em periódicos

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