Add reference line on the graph created by proc glm

[monona]

proc glm data=work.data_1;
	class z;
	model y=w z;
run;

Appreciate if anyone could let me know how to add to the plot horizontal lines correspondent means for y in each group z.

[PeterClemmensen]

I don't think such a facility is available in GLM. I think you have to pre calculate the mean values for each group and use the REFLINE Statement in PROC SGPLOT.

[Ksharp]

Save it as a dataset by :

ods output ANCOVAPlot=want;
proc glm data=sashelp.class;
class sex;
model weight =sex height;
quit;

and plot refline via PROC SGPLOT .