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Posterior distribution

PostPosted: Fri Jun 03, 2016 12:20 am
by jolee
Hi everyone,

I am getting very narrow posterior distributions (90% interval <0.0001) and the trace plots seem to move only around the starting points.

Why am I getting this problem and how can I fix it?

Thanks,
jolee

Re: Posterior distribution

PostPosted: Fri Jun 03, 2016 7:51 am
by jpfeifer
Your MCMC did not correctly sample from the posterior, potentially because the MCMC jumping covariance or mh_jscale were too small. Did the mode-finding work? How was the acceptance rate?

Re: Posterior distribution

PostPosted: Sat Jun 04, 2016 4:57 am
by jolee
Yes, jscale is small (0.011666) and acceptance rates are 32.66% and 32.74%.

Mode finding is not working at all and most of the likelihood functions are linear. Is that the matter of my data?

Thank you so much for your help.

Re: Posterior distribution

PostPosted: Sun Jun 05, 2016 6:38 pm
by jpfeifer
It is hard to say. Please recheck your model and the observation equations and try different mode finders. You also might want to try the
Code: Select all
MCMC_jumping_covariance
option.