For each variable in y that is a factor, a plot is drawn. When boxplots are drawn
the colors, that can be supplied by col
are used to display different
factor levels.
For scatterplots it is also possible to use the plotting symbols, specified by
pch
for that.
If the colors and for scatterplots the plotting symbols are not supplied,
they will be automatically generated. However, the plotting symbols will only
be automatically used in this way if there are up to seven different levels.
If colors or the plotting symbols are supplied, but the number of factor levels
is bigger than the the number of different values, they will be replicated.
Sometimes the legends might be only partially visible, especially when the width
of the graphics device is too small. To fix this, create a graphics device with
a larger width (see help("device") for on available devices and their details)
and then repeat the
plotMvaFactor
command.