This section illustrates how to modify axis tick marks and control grid lines. For example, you can specify the following statement to request tick marks ranging from –4 to 2 in the Y-axis:

layout Overlay / yaxisopts=(linearopts=(tickvaluelist=(-4 -3 -2 -1 0 1 2)));

The LINEAROPTS= option is used for standard linearly scaled axes (as opposed to log-scaled axes). You use the TICKVALUELIST= to specify the tick marks.

You can control the grid lines by using the GRIDDISPLAY= suboption in the YAXISOPTS= option. Typically, you specify either GRIDDISPLAY=AUTO_OFF (grid lines are not displayed unless the GraphGridLines element in the current style contains DisplayOpts="ON") or GRIDDISPLAY=AUTO_ON (grid lines are displayed unless the GraphGridLines element in the current style contains DisplayOpts="OFF"). Here, the template is modified by specifying GRIDDISPLAY=AUTO_ON for both axes. The following statements produce Output 22.1.6:

proc template;
   define statgraph Stat.Robustreg.Graphics.QQPlot;
      notes "Q-Q Plot for Standardized Robust Residuals";
      dynamic _DEPLABEL Residual;
      BeginGraph;
         entrytitle "Analysis of Residuals";
         layout Overlay / yaxisopts=(gridDisplay=Auto_On
            linearopts=(tickvaluelist=(-4 -3 -2 -1 0 1 2))
            label=("Standardized Robust Residual for " _DEPLABEL))
            xaxisopts=(gridDisplay=Auto_On label="Quantile");
            SCATTERPLOT y=eval (SORT(DROPMISSING(RESIDUAL))) x=eval(
               PROBIT((NUMERATE(SORT(DROPMISSING(RESIDUAL))) -0.375)/(0.25
               + N(RESIDUAL)))) / primary=true
               markerattrs=GraphDataDefault(symbol=CircleFilled)
               rolename=(q=eval (
               PROBIT((NUMERATE(SORT(DROPMISSING(RESIDUAL))) -0.375)/(0.25
               + N(RESIDUAL)))) s=eval (SORT(DROPMISSING(RESIDUAL))))
               tip=(q s) tiplabel=(q="Quantile" s="Residual");
            lineparm slope=eval (STDDEV(RESIDUAL)) Y=eval (MEAN(RESIDUAL))
               X=0 / lineattrs=GraphReference(color=red pattern=dash)
                     extend=true;
         EndLayout;
      EndGraph;
   end;
run;

ods graphics on;

proc robustreg data=stack plots=qqplot;
   ods select QQPlot;
   model y = x1 x2 x3;
run;

You can restore the default template by running the following step:

proc template;
   delete Stat.Robustreg.Graphics.QQPlot / store=sasuser.templat;
run;

See the section Modifying the Style to Show Grid Lines for more information about grid lines.