[SciPy-User] probplot's return value r or r^2?

mikey abc.mikey@googlemail....
Thu Feb 18 07:59:56 CST 2010


Hi there,

Hopefully you can help me with a couple of things I'm not getting
about scipy's stats package. Both of which are shown on this image:
http://img198.yfrog.com/img198/8928/normalqqplotsection3tot.png

Firstly I want to know what is returned by the r value from probplot?
The documentation says that it returns r but if you have it plot the
graph for you it plots r^2. If you compare them you find that the
returned value r and the plotted result for r^2 are the same, so which
is it?

Also I'm trying to work out what the p value from the shapiro test are
showing me. I've plotted the W and p values from the test on my
probplot for my data  and the probplot shows a good correlation
between my data and the expected distribution for normal data but p is
too low to accept the null hypothesis that it is normal. Am I
interpereting what it's showing me properly, or is it just my data?

Thanks for your help,

Mikey


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