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 77.8.5 demonstrates this style of key.
You can reproduce Output 77.8.5 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 77.8.17:
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 77.8.18.
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 77.8.19.
Finally, you can attach labels directly to curves with the KEY= ONCURVES option. The following PLOT statement produces Output 77.8.20:
plot x=n min=20 max=500 key = oncurves;