R help - Jul 2009 - calculating p-values from t-values for a Bonferroni adjustment

I am performing a sequential bonferroni adjustment on the results of an
ANCOVA but the equation I have for calculating p-values from the t-values is
not working.  I can't seem to find it anywhere else. This is the code I have
now: 2*(1-pt(t,df)) where t=t-value and df=degrees of freedom from the
ANCOVA. Is there an error in the code? maybe another way to find the
p-values? Help!
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NativeBuff2003 wrote:
> 
> I am performing a sequential bonferroni adjustment on the results of an
> ANCOVA but the equation I have for calculating p-values from the t-values
> is not working.  I can't seem to find it anywhere else. This is the
code I
> have now: 2*(1-pt(t,df)) where t=t-value and df=degrees of freedom from
> the ANCOVA. Is there an error in the code? maybe another way to find the
> p-values? Help!
> 
Please tell us what "not working" means and give a reproducible (?)
example,
etc., as discussed
in the posting guide.  Perhaps you have redefined the pt() function by
accident?

 Works fine for me, e.g. 
> 2*(1-pt(2,10))
[1] 0.07338803

2*pt(abs(x),df,lower.tail=FALSE)  would be slightly more general/accurate.

   Ben Bolker

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