Classification of coefficients of variation in experiments with commercial layers

Abstract

This study aimed at determining a specific classification of coefficients of variation in experiments with commercial layers. Coefficients of variation were collected from papers published in Brazilian journals between 2000 and 2009 for performance, internal egg quality, and eggshell quality parameters. The coefficients of variation of each parameter were classified as low, intermediate, high, and very high according to the ratio between the median and the pseudo-sigma. It was concluded that the parameters used in experiments with commercial layers have a specific classification of coefficients of variation, and that this must be considered to evaluate experimental accuracy.

Methods for classifying coefficients of variation in experimentation with poultrys

“…The variable egg weight (Table 7) shows the lowest CV values, corroborating with data from Faria Filho et al (2010), indicating higher accuracy in all methods, since according to Cargnelutti Filho & Storck (2007) the lower the CV, the greater the precision of the experiment and vice versa, and the higher the precision, the higher the experimental quality.…”

“…It is noteworthy that Pimentel-Gomes (2009) was based on agronomic parameters. Faria Filho et al, (2010) found a smaller range varying in the high classification, from 3.98 to 5.04%.…”

Classification of the coefficients of variation of parameters evaluated in Japanese quail experiments

“…This difference may be due to the fact that the proposal of Gomes (2000) is based on agronomic parameters. Moreover, there is considerable variation among animal species, and there are specific classifications for pigs (Judice et al, 1999), beef cattle (Judice et al, 2002), equine nutrition (Lana et al, 2006), broilers (Mohallem et al, 2008), and commercial layers (Faria Filho et al, 2010).…”

“…In experiments with Japanese quails, there are reference values of specific CV that identify classification ranges relative to their degree of precision, as it happens in pig production (Judice et al, 1999), beef cattle (Judice et al, 2002), equine nutrition (Lana et al, 2006), broilers (Mohallem et al, 2008), and commercial layers (Faria Filho et al, 2010).…”

Prediction of rainfall from geographical coordinates of the state of Rio Grande do Sul

“…Os coeficientes de variação (C.V.) da precipitação mensal, sazonal e anual mostram que a variabilidade desse atributo é considerada, segundo Faria Filho et al (2010), média (10% < C.V.< 20%), com valores que variam de 11,33 a 18,99%, para o mês de fevereiro e dezembro, respectivamente. Silva et al (2003), com o objetivo de estudar o comportamento temporal das chuvas mensais de Uberaba/MG, utilizando a série das precipitações pluviais mensais e anuais de 1914 a 2000, encontraram valores de C.V. relativamente altos, principalmente na estação seca, com valores de 61,37 e 161,08%.…”