Dear people,
I've a problem in doing a power calculation. In Fryer and Nicholson
(1993), ICES J. mar. Sci. 50: 161-168 page 164 an example is given with
the following characteristics
T=5, points in time
R=5, replicates
Var.within=0.1
q=10, a 10% increase per year
The degrees of freedom for the test are calculated as Vl=T*R-2=23 and
the non-centrality parameter Dl=4.54.
Using this they get a power of 0.53, but the result that I'm getting is
0.05472242.
I've tried this several ways in R, but I'm not able to come up with the
same number. Am I doing something wrong in the calculation of the power?
Here's my code:
T<-5
R<-5
sigmasq<-0.1
q<-10
Vl<-(T*R)-2
Dl<-(R*(T-1)*T*(T+1)/(12*sigmasq))*(log(1+(q/100)))^2 #Dl result is
still similar
power.1<-1-pf(qf(.95,(T*R-2),1,ncp=0),(T*R-2),1,ncp=Dl)
Thank you for any suggestions/help.
I'm using R2.4.1, on windowsXP.
Erik Meesters
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