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How many parameters can a Jags model have?
JAGS models can get complex and often have many (hundreds or thousands) of parameters. Here we will specify that we want to monitor both parameters in this model, but in the future, you may want to specify only some parameters of interest. The command jags () runs the model, with the arguments below.
What’s the difference between gamma and Poisson regression?
The key difference between Gamma and Poisson regression is how the mean/variance relationship is encoded in the model. The Poisson approach models the variance as being proportional to the mean, the Gamma approach models the standard deviation as being proportional to the mean.
Which is the best way to plot Jags output?
There are a number of packages that can also be used to plot JAGS output and make things simpler. However, it is not a bad idea to become comfortable with the JAGS model object as there may come a model that has sufficiently complex output that a canned diagnostic does not work. Gelman, Andrew, and Jennifer Hill. 2006.
How is Jags not a procedural language like R?
JAGS does the rest… JAGS is not a procedural language like R; you can write the model code in any order Define model in BUGS language (write in R and export as text file to be read by JAGS) Define parameters to keep track of (i.e., parameters of interest)
What should I bundle my data into for Jags?
We need to bundle our data into a list that JAGS will be able to read. This is very simple in this exercise and generally very simple in more complex models. Just make sure you have all the elements in that the model needs, which may extend beyond data.
How to generate random starting values in Jags?
Just make sure you have all the elements in that the model needs, which may extend beyond data. Using an equals sign (not assignment operator), set the data that JAGS is looking for on the left side, to the input data on the right side. JAGS will generate random starting values if not specified, and for simple models this should work.