|void erfgrid (ymin, ystep, ymax, yformat)||ERFPLT.C||Level 2|
|float ymin||The minimum data value for the y axis.|
|float ystep||The change in y between tick marks on the y axis.|
|float ymax||The maximum data value for the y axis.|
|char *yformat||The y axis format string.|
|The routine erfgrid() draws the axes and grid lines that appear
on ERF or percent paper. The x axis of an ERF plot
is scaled on cumulative percentage. The y axis is scaled linearly. Thus, the user has control over the y axis scaling only. Results for a normal (Gaussian) distribution (a bell-shaped curve) are expected to be a straight line on the ERF grid. The arguments for this routine are similar to the y axis parameters of the graf() routine.