Step C9: Format and parameter selection for the time elapsed between
two parameters I
To view a plot of an estimate of the time elapsed between parameters we
need to select "Posterior probability density plot" for the "Format type".
We also need to select two parameters. As an example, we'll look
at the time elapsed between the arrival of the Polynesians and the creation
of the fishpond. For this we would need to select phi 1 (which corresponds
to the arrival date of the Polynesians) and also alpha 2 (which corresponds
to the date of the creation of the pond).