an integer specifying which side of the plot the axis is
to be drawn on. The axis is placed as follows: 1=below, 2=left, 3=above and
4=right.
formula
the formula to be converted. Should be of the form y ~ f(x)
at.maj
a vector of the position and labels of the major ticks
at.min
a vector of the position of minor ticks
labels
his can either be a logical value specifying whether
(numerical) annotations are to be made at the major tickmarks, or a character
or expression vector of labels to be placed at the major tickpoints.