On Nov 2, 2009, at 10:40 AM, carol white wrote:
Hi,
We could use qqplot to see how two distributions are different from
each other. To show better how they are different (departs from the
straight line), how is it possible to plot the straight line that
goes through them? I am looking for some thing like qqline for
qqnorm. I thought of abline but how to determine the slope and
intercept?
I always assumed that the intercept was zero and the slope = unity.
y <- rt(200, df = 5)
qqnorm(y); qqline(y, col = 2)
qqplot(y, rt(300, df = 5))
abline(0, 1, col="red")
I am open to education if that assumption is too simplistic, but you
have not offered anything in the way of a counter-example.
==
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
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