TITLE(abline @@ Add a Straight Line to a Plot)
USAGE(
abline(a, b, DOTS)
abline(h=, DOTS)
abline(v=, DOTS)
abline(coef=, DOTS)
abline(reg=, DOTS)
)
ALIAS(abline)
VALUE(
This function is invoked for its side effects, which
is to add one or more straight lines through the
current plot.
The first form above specifies the line in intercept/slope
form (alternatively LANG(a) can be specified on its own and is taken
to contain the slope and intercept in vector form).
The LANG(h=) and LANG(v=) forms draw horizontal and vertical lines
at the specified coordinates.
The LANG(coef) form specifies the line by a vector containing
the slope and intercept.
LANG(reg) is a regression object which contains LANG(reg$coef).
If it is of length 1 then the value is taken to be the slope of a
line through the origin, otherwise, the first 2 values are
taken to be the slope and intercept.
PARA
The graphical parameters LANG(col) and LANG(lty)
can be specified as arguments to LANG(abline);
see LANG(par) for details.
)
EXAMPLES(
data(cars)
z <- lm(dist ~ speed, data=cars)
plot(cars)
abline(z)
)
