R help - Sep 2009 - Plotting two qqnorm plots:

Hi all,

Does anyone know how to plot overlapping qqnorm plots on the same window?
Suppose I have data in the vector x and y:

qqnorm(x)
lines(qqnorm(y))

I though these two lines will do the job... However, lines doesn't seem to
work. Anyways, thanks in advance!
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You can do this in lattice:

library(lattice)
df = data.frame(val = rnorm(100), group = rep(c('x', 'y'), each
= 50))
qqmath(~val, groups = group, data = df)

Hope that helps,

Greg

njhuang86 wrote:
> Hi all,
>
> Does anyone know how to plot overlapping qqnorm plots on the same window?
> Suppose I have data in the vector x and y:
>
> qqnorm(x)
> lines(qqnorm(y))
>
> I though these two lines will do the job... However, lines doesn't seem
to
> work. Anyways, thanks in advance!
>   
-- 
Greg Hirson
ghirson at ucdavis.edu

Graduate Student
Agricultural and Environmental Chemistry

1106 Robert Mondavi Institute North
One Shields Avenue
Davis, CA 95616