Dear Jarrod,

 

I have a data set where residual have a  heavy-tailed distribution with
some extreme residual values and consequently the distribution deviates
from the Gaussian one.

Is it possible to include an skewed-normal density for the residual in
MCMCglmm package?

I have done the analysis of this data with both ASReml & MCMCglmm. The
results are similar and outcome from MCMCglmm analysis doesn't change
with change in prior.

While MCMCglmm with large numbers of iterations (400000) provides an
appropriate posterior distribution for the variance components which
include additive animal additive effect and common full-sib effects, the
chain doesn't mix well as it is judged by the autocorrelation. 

The Box-Cox transformation of data suggests a square root
transformation. When I analysed the square root transformed data the
chain mix well, distributions are OK, but results change when different
prior. 

 

Alex 

 

 

Dr Alex Safari

Aquaculture and Genetic Improvement 

The WorldFish Center, Penang, MALAYSIA 

Telephone: 60 4 620 2175 

Fax: 60 4 626 5530  (GMT +8)

e-mail: a.safari@cgiar.org

http://www.worldfishcenter.org <http://www.worldfishcenter.org/>  

Reducing poverty and hunger by improving fisheries and aquaculture

 


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