

   FFoorrmmuullaa NNoottaattiioonn ffoorr SSccaatttteerrpplloottss

        plot.formula(formula, data = NULL, subset, na.action, ..., ask = TRUE)
        plot(y ~ x, ...)

   AArrgguummeennttss::

    formula: a `formula', such as `y ~ x'.

       data: a data.frame (or list) from which the variables in
             `formula' should be taken.

     subset: an optional vector specifying a subset of observa-
             tions to be used in the fitting process.

   na.action: a function which indicates what should happen
             when the data contain `NA's.  The default action
             (`na.omit') is to omit any incomplete observa-
             tions.  The alternative action `na.fail' causes
             `plot' to print an error message and terminate if
             there are any incomplete observations.

        ...: graphical parameters may also be passed as argu-
             ments, see `par'. These can include `ylab', which
             if not supplied is set by `plot.formula'.

        ask: logical, see `par'.

   VVaalluuee::

        This function is invoked for its side effect of drawing
        a scatter plot in the active graphics window.

   SSeeee AAllssoo::

        `plot.default', `plot.factor'.

   EExxaammpplleess::

        data(swiss)
        op <- par(mfrow=c(2,1))
        plot(Fertility ~ Education, data = swiss)
        plot(Fertility ~ Education, data = swiss, subset = Education < 20)
        par(op)

