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A Poisson–Gamma model for analysis of ecological non-negative continuous data.
- Source :
- Environmental & Ecological Statistics; Dec2013, Vol. 20 Issue 4, p533-552, 20p
- Publication Year :
- 2013
-
Abstract
- The statistical analysis of continuous data that is non-negative is a common task in quantitative ecology. An example, and our motivation, is the weight of a given fish species in a fish trawl. The analysis task is complicated by the occurrence of exactly zero observations. It makes many statistical methods for continuous data inappropriate. In this paper we propose a model that extends a Tweedie generalised linear model. The proposed model exploits the fact that a Tweedie distribution is equivalent to the distribution obtained by summing a Poisson number of gamma random variables. In the proposed model, both the number of gamma variates, and their average size, are modelled separately. The model has a composite link and has a flexible mean-variance relationship that can vary with covariates. We illustrate the model, and compare it to other models, using data from a fish trawl survey in south-east Australia. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 13528505
- Volume :
- 20
- Issue :
- 4
- Database :
- Complementary Index
- Journal :
- Environmental & Ecological Statistics
- Publication Type :
- Academic Journal
- Accession number :
- 91993215
- Full Text :
- https://doi.org/10.1007/s10651-012-0233-0