Data-dependent Reference line in GPL

Posted by Kirill Orlov on Oct 16, 2021; 1:39pm
URL: http://spssx-discussion.165.s1.nabble.com/Data-dependent-Reference-line-in-GPL-tp5740795.html

How do we plot via GPL a reference line at some data-dependent statistic value, say, at the mean of the data values plotted?