Produce a Line through a Normal QQ-Plot
DESCRIPTION:
This function fits and plots a line through a normal QQ-plot.
USAGE
:
qqline(x, ...)
REQUIRED ARGUMENTS
:
x
:
a numeric vector, typically a residual vector.
OPTIONAL ARGUMENTS
:
...
:
graphics parameters may be passed to
abline
(which actually draws the line).
VALUE
:
a vector (returned invisibly) containing the intercept and slope of the line.
SIDE EFFECTS:
plots a line through the first and third quartile of the data, and the corresponding quantiles of the standard normal distribution.
DETAILS:
This is generally used after a call to
qqnorm
.
SEE ALSO:
qqnorm
,
qqplot
,
abline
.
EXAMPLES
:
qqnorm(car.time) qqline(car.time, col=3)