qqnorm(y, ...) qqline(y, ...) qqplot(x,y, plot.it = T, ...)
qqnorm produces a normal QQ plot of the values in y.
qqline adds a line to a normal quantile-quantile plot
which passes through the quartiles.
Graphical parameters may be given as arguments to qqnorm, qqnorm
and qqline.
ppoints.