Centile estimation for a proportion response variable. (4th October 2015)

• Record Type: Journal Article
• Authors: Hossain, Abu; Rigby, Robert; Stasinopoulos, Mikis; Enea, Marco
• Is Part Of: Statistics in medicine. Volume 35:Number 6(2016)
• Page Start: 895
• Page End: 904
• Publication Date: 2015-10-04
• Subjects: beta inflated distribution -- fractional data -- GAMLSS -- generalised Tobit model -- logit skew Student t distribution; Medical statistics -- Periodicals; Statistique médicale -- Périodiques; Statistiques médicales -- Périodiques; 610.727
• DOI: 10.1002/sim.6748
• Languages: English
• ISSNs: 0277-6715

Abstract

Abstract : This paper introduces two general models for computing centiles when the response variable Y can take values between 0 and 1, inclusive of 0 or 1. The models developed are more flexible alternatives to the beta inflated distribution. The first proposed model employs a flexible four parameter logit skew Student t ( logitSST ) distribution to model the response variable Y on the unit interval (0, 1), excluding 0 and 1. This model is then extended to the inflated logitSST distribution for Y on the unit interval, including 1. The second model developed in this paper is a generalised Tobit model for Y on the unit interval, including 1. Applying these two models to(1‐ Y ) rather than Y enables modelling of Y on the unit interval including 0 rather than 1. An application of the new models to real data shows that they can provide superior fits. Copyright © 2015 John Wiley & Sons, Ltd.