Date:         Fri, 25 Oct 2002 10:51:10 +0200
Reply-To:     Asesoría Bioestadística
              <bioestadistica@eresmas.net>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         Asesoría Bioestadística
              <bioestadistica@eresmas.net>
Subject:      Re: Some formulae needed (...and obtained)
Content-Type: text/plain; charset=us-ascii

Hi all:

It seems that after all, you had given the information I needed, but I did not
recognize it ;) (still a bit asleep)

Using the harmonic mean formula provided, I finally get this formulae for n1
and n2:

k=n2/n1 (ratio)

n1=n*(1+k)/2k
n2=n*(1+k)/2

If k=1 n1=2n/2=n and n2=2n/2=n
If k=2: n1=3n/4 and n2=3n/2
If k=3: n1=4n/6 (2n/3) and n2=4n/2=2n

I have tested the macro with other sample size programs I know and it gives the
expected results.

Thanks

Marta Garcia-Granero