The POWER Procedure

The default style for the key (or “legend”) is one that displays the association between levels of features and levels of analysis parameters, located below the X axis. For example, Output 75.8.5 demonstrates this style of key.

You can reproduce Output 75.8.5 with the same key but a different location, inside the plotting region, by using the POS=INSET option within the KEY=BYFEATURE option in the PLOT statement. The following statements product the plot in Output 75.8.17:

proc power plotonly;
   twosamplemeans test=diff
      groupmeans   = 12 | 15 18
      stddev       = 7 9
      power        = .
      ntotal       = 200;
   plot x=n min=20 max=500
      key = byfeature(pos=inset);
run;

Alternatively, you can specify a key that identifies each individual curve separately by number by using the KEY=BYCURVE option in the PLOT statement:

   plot x=n min=20 max=500
      key = bycurve;

The resulting plot is shown in Output 75.8.18.

Use the NUMBERS=OFF option within the KEY=BYCURVE option to specify a nonnumbered key that identifies curves with samples of line styles, symbols, and colors:

   plot x=n min=20 max=500
      key = bycurve(numbers=off pos=inset);

The POS=INSET suboption places the key within the plotting region. The resulting plot is shown in Output 75.8.19.

Finally, you can attach labels directly to curves with the KEY=ONCURVES option. The following PLOT statement produces Output 75.8.20:

   plot x=n min=20 max=500
      key = oncurves;