panel.stripplot(x, y, jitter.data=F, ...)

x:

horizontal coordinates of points to be plotted.

y:

vertical coordinates of points to be plotted (constant for each group).

jitter.data:

should the y values be jittered? If true, the function jitter is called to give some vertical displacement to the points, potentially alleviating overplotting.

...:

graphical parameters passed to points to draw the 1-dimensional scatter plots. By default, the trellis parameter list plot.symbol will be used to control character size (cex), plotting symbol (pch), font, and color (col).