Produces a plot with the levels of one factor along the x-axis, the response
on the y-axis and the points corresponding to a particular level of a second
factor connected by lines.
This type of plot is useful for exploring or discovering interactions.
vector containing the response.
Missing values (NA) are allowed.
OPTIONAL ARGUMENTS:
fun=
a function or the name of a function. This should be a
summary function returning one number on each call.
trace.label=
labels for levels of factor plotted as traces.
fixed=
logical flag: if
TRUE, the legend is in the order of the levels of the
trace factor.
Otherwise, it is in the order of the traces at the right end of the plot.
Graphical parameters may also be supplied as arguments to
this function (see
).
Of particular use is
lty which has a
default value of nc:1 where
nc is the number of levels of
trace.factor.
The parameter for color,
col, may also be a vector of integers for this
function.
In addition, the high-level graphics arguments described under
and the arguments to
may be supplied to this function.
SIDE EFFECTS:
a plot will be created showing the requested function of responses
for each level of the second factor at each level of the first factor.
By default, lines for each value of the trace factor are drawn in different
styles so that they may be more easily distinguished.
DETAILS:
Lines will not be drawn to or from any points that involve a missing value.