From: <ManuelPerera-Chang_at_fmc-ag.com>

Date: Fri 26 May 2006 - 22:57:02 EST

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri May 26 23:03:59 2006

Date: Fri 26 May 2006 - 22:57:02 EST

There a suggested sample size strategy uses the formula

0.30/0.45=F(0.80,2n,2n)/F(0.025,2n,2n)

which gives n=96, as in the book.

(here F(alfa,k,n) is the upper (alfa)th quantile of an F distribution with k,n degrees of freedom)

I have been trying to get n=96 using the following code in R.

val<-rep(NA,200)

for (n in 1:200) {

val[n]<- qf(0.8, 2*n, 2*n,lower.tail = TRUE, log.p = FALSE)/qf(0.025,
2*n, 2*n,lower.tail = TRUE, log.p = FALSE);
}

but val doesnot get any close to 0.30/0.45.

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri May 26 23:03:59 2006

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