Vector of amounts to jiggle the points horizontally,
or a character string ("fixed" or "random")
indicating the jiggling method; see jiggle().
max_jiggle
Maximum jiggle value; passed to jiggle() as argument maxvalue.
rotate
If TRUE, have group as y-axis; default (FALSE) has
group on x-axis.
...
Optional graphics arguments
Details
Calls grayplot() with special choices of
graphics parameters for the case of categorical x.
If group is a factor, the order of the groups is as in the
levels. Otherwise, we take sort(unique(group)). So if you want to
control the order of the levels, make group a factor with the levels
in the desired order, for example group <- factor(group, levels=unique(group)).