# [R] two-sided p-value?

Uwe Ligges ligges at statistik.tu-dortmund.de
Sun Oct 16 13:54:42 CEST 2011

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On 16.10.2011 13:08, Laura wrote:
> Dear all,
>
> I am a little bit confused because of the returned p-value by summary.lm and
> also summary.rq
>
> I thought if the pvalue is<= 0.05 the difference is significant. But the R
> help says it is a two-sided pvalue. So does that mean the pvalue has to be
> <= 0.025 and>= 0.975?

And at the same time. ;-)

Actually, the hypothesis is a two sided one, the p-value should still be
smaller than your predefined alpha that may or may not be 0.05. If that
is not yet clear, you should really ask for local statistical advice or
start reading yourself some statistics textbooks.

Best,
Uwe Ligges

>
>
> Best, Laura
>
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