Not particularly R related, but r related.
For pearson correlation, the test statistics is based on t distribution.
ts = r * sqrt ((n-2)/(1-r^2))
with n-2 degree of freedom.
I think you can solve this question, maybe a little bit of googling.
On Jan 14, 2008 1:39 PM, Sanglamt <sanglant at mchsi.com>
wrote:>
> I've spent several hours trying to track the answer down myself and
failed
> miserably so a simple question for everyone that will no doubt have a
> painfully obvious answer.
>
> What's the command to calculate the critical value of r using a two
tailed
> test with a given alpha and degrees of freedom? I.e., alpha=0.05, df=18,
> two-tailed test, with the result being 0.4438
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--
CH Chan
Research Assistant - KWH
http://www.macgrass.com