Volume no :8, Issue no: 2, December (2012)

ON ESTIMATED MEANS FOR EXPERIMENTS WITH BETA RESPONSE

Author's: LUIS FERNANDO GRAJALES, RAYDONAL OSPINA and LUIS ALBERTO LĂ“PEZ
Pages: [105] - [130]
Received Date: December 20, 2012
Submitted by:

Abstract

Many factorial experiments include continuous responses restricted to the interval such as percentages, rates and indices mainly found in industry and medicine. In order to explain the response for some factors, usually the analysis of variance (ANOVA) is the most common technique because the response is considered normally distributed. However, normality and constant variance for errors is difficult to achieve for response in This paper used beta regression models from frequentist and Bayesian perspectives to estimate mean response for factorial experiments with response in The methodology is also compared with normal regression models. Numerical results exhibit that coverage of intervals with logit transformation was as good as the best function link for beta regression. Also, Bayesian and frequentist lengths of intervals are similar for logit link. The Bayesian model with probit link presented the worst performance with respect to lengths of intervals.

Keywords

Bayesian analysis, beta regression model, confidence intervals, experimental design, fractional factorial, rates, transformations.