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We present motivation and new Stata commands for modeling count data. While the focus of this article is on modeling data with underdispersion, the new command for fitting generalized Poisson regression models is also suitable as an alternative to negative binomial regression for overdispersed data.
Persistent link: https://www.econbiz.de/10010630741
Overdispersion and correlation are two features often encountered when modeling non-Gaussian dependent data, usually as … acknowledges the presence of dependency and overdispersion by way of two separate sets of random effects. A marginally specified … comfort of marginally meaningful parameters and the ease of allowing for overdispersion and correlation. Apart from model …
Persistent link: https://www.econbiz.de/10010574444
In sets of count data, the sample variance is often considerably larger or smaller than the sample mean, known as a problem of over- or underdispersion. The focus is on hierarchical Bayesian modeling of such longitudinal count data. Two different models are considered. The first one assumes a...
Persistent link: https://www.econbiz.de/10010580853
Vector generalized linear models (VGLMs) as implemented in the vgamR package permit multiple parameters to depend (via inverse link functions) on linear predictors. However it is often the case that one wishes different parameters to be related to each other in some way (i.e., to jointly satisfy...
Persistent link: https://www.econbiz.de/10010719656
Purpose – The purpose of this paper is to introduce the zero-modified distributions in the calculation of operational value-at-risk. Design/methodology/approach – This kind of distributions is preferred when excess of zeroes is observed. In operational risk, this phenomenon may be due to the...
Persistent link: https://www.econbiz.de/10010720095
Persistent link: https://www.econbiz.de/10008925208
in the presence of measurement errors, in general, maximum likelihood estimator of the overdispersion using the observed …
Persistent link: https://www.econbiz.de/10009145687
Persistent link: https://www.econbiz.de/10008775823
Persistent link: https://www.econbiz.de/10008674007
Using estimation of demand for the George Washington/Jefferson National Forest as a case study, it is shown that in a stratified/clustered on-site sample, latent heterogeneity needs to be accounted for twice: first to account for dispersion in the data caused by unobservability of the process...
Persistent link: https://www.econbiz.de/10009021105