Plots the points in and outside of the intervals
based on Yp points and also the PE proximity regions
(i.e., intervals).
PE proximity region is constructed with expansion parameter \(r \ge 1\) and
centrality parameter \(c \in (0,1)\).
If there are duplicates of Yp or Xp points,
only one point is retained for each duplicate value,
and a warning message is printed.
For better visualization, a uniform jitter from \(U(-Jit,Jit)\)
(default is \(Jit=.1\)) times range of Xp
and Yp and the proximity regions (intervals)) is added to the
\(y\)-direction.
centers is a logical argument, if TRUE,
plot includes the centers of the intervals as vertical lines in the plot,
else centers of the intervals are not plotted.
See also (ceyhan:metrika-2012;textualpcds).