BCal help system: The Tutorial


Step C4: Viewing posterior density plots for individual parameters
We now see a plot of the posterior probability distribution for alpha 2.
The densest area of the plot shows the most likely calendar dates for the
event represented by this parameter. From the plot we can see that
the most likely calendar dates are in the range 60010 cal BP. Recall
that we provided absolute a priori chronological information that
beta 2 is exactly 9 cal BP (1941 AD). This means that all dates at
this site are constrained to be earlier than 9 cal BP. The obvious
consequences of this can be seen at the righthand end of our plot.
As well as viewing the posterior probability distribution as a plot,
we can view the distribution as a highest posterior density (HPD) region.
To do this, we must move back to the format and parameter selection page
by selecting "Back" (for the tutorial you should select "Next" to continue).
Note: The smoothness of the graph depends partly on the bin widths you
set when you submit the job for calibration. If you want smoother (or
less smooth) results you need to resubmit your job, setting the bin
widths appropriately.