[R] confidence interval in "predict.lm"

[Peter Dalgaard BSA]

Matej Cepl <matej at ceplovi.cz> writes:

> Thomas Lumley wrote:
> > You asked R for a confidence interval for the predicted mean at x.  If you
> > want a prediction interval at x you need  interval="prediction" not
> > interval="confidence".
> 
> Slightly OT question to this thread:
> 
> How can I get critical values for given distribution density?
> E.g. function f which would give me 2.228 for ft(p=0.05,df=10)
> (i.e., t for student distribution with given level probability).

> qt(p=0.975,df=10)
[1] 2.228139


-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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