panel diagram -------------
panel , by( <varlist> ) function(string) graph_options
Panel performs the same function as a by option in a graph funtion. It will draw the diagrams for each level of the by variable as a panel diagram. I.e. the graphs will be in a matrix layout without spaces in the interior of this layout. This leaves possible labelling of axes to the edges of the matrix. Any specification of the xlabels, ylabels and rlabels will affect every graph drawn. Hence the user can specify the same scales for every graph.
by is necessary otherwise there would only be one graph drawn and hence the appropriate commands should be used and not panel.
function this specifies the diagram command. The default is the command graph however the following commands can also be used histogram, qnorm.
.panel y, function(histogram) by(levels)
.panel y x, by(z)
.panel y x , by(z) xlab(1,2,3,4) ylab(2,3,4,5)
Also see --------