[R] error message

[forkusam]

 I am trying to calculate n, using power.t.test

power.t.test(n=NULL,delta=delta, sd=sigmaEins,
sig.level= alpha, power=power, type=c("two.sample"),
alternative=c("two.sided"))

The values of the parameter are read in from a file.
 I have no idea what the error message means.

--- Peter Dalgaard <p.dalgaard at biostat.ku.dk> wrote:
> forkusam <forkusam at yahoo.com> writes:
> 
> >  Hi,
> > Can someone please tell me what such an error
> message
> > could mean. i.e where a problem must have arised.
> > 
> > Error in uniroot(function(n) eval(p.body) - power,
> > c(2, 1e+07)) : 
> >         f() values at end points not of opposite
> sign
> 
> Looks like the innards of one of the power
> calculations, finding n to
> achieve a given power. You'd likely get an error
> like that if the
> power is not between 0 and 1, but how about telling
> us what you were
> trying to do?
> 
> -- 
>    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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