stripplot. Also see
panel.superpose
panel.stripplot(x, y, jitter.data = FALSE, factor = 0.5, amount = NULL, horizontal = TRUE, groups = NULL, ..., identifier = "stripplot")panel.xyplot, using its jitter.x or
jitter.y argument (depending on the value of
horizontal). jitterbwplot for a fuller
explanation.
panel.xyplot x
for each level of y (or vice versa, depending on the value of
horizontal)
stripplot, jitter