Message-ID: <539EE33E.7020700@senckenberg.de>
Date: 2014-06-16T12:29:50Z
From: Bob OHara
Subject: probability distribution for zero-inflated, right skewed data
In-Reply-To: <9BAC002D-E288-427B-90ED-01B1C69519A3@gmail.com>
On 16/06/14 13:57, Johannes Bj?rk wrote:
> Dear all,
>
> Im looking into how to fit a GLM model (Im using rjags) with data that are heavily right skewed. In addition, some variables also zero-inflated. The data are species area distribution measured as "total area (km^2)" which is subsetted into "area in tropical zone" and "area in temperate zone". The last two variables contain zeros.
>
> I have google zero-inflated models... and most that come up is "zero-inflated negative binomial" and zero-inflated negative poisson" for count data. I reckon I cannot use any of these distributions since my variables are not discrete.
>
> Any pointer to which distribution(s) that might fit this kind of data would be much appreciated.
I think a Tweedie distribution is sometimes used, but that always makes
me think of escaping chickens. Recently this was published, which might
also be useful:
<http://onlinelibrary.wiley.com/doi/10.1111/2041-210X.12122/abstract>.
They used BUGS, so you could ask them if the code is available. Even if
it isn't, it shouldn't be too difficult to code up.
Bob
--
Bob O'Hara
Biodiversity and Climate Research Centre
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