Date:         Thu, 22 Sep 2005 19:28:16 +0200
Reply-To:     Marta García-Granero
              <biostatistics@terra.es>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         Marta García-Granero
              <biostatistics@terra.es>
Organization: Asesoría Bioestadística
Subject:      Re: Standard Error
In-Reply-To:  <s3328705.086@gwdom2-med.med.utah.edu>
Content-Type: text/plain; charset=ISO-8859-15

Hi Adrian,

Sorry, there was a bit typo error in my formula. The correct one is:

SE(diff)= SQRT(MSwithin)*SQRT((1/n1+1/n2))
        = SQRT(2*MSwithin/n) if sample sizes are equal (n1=n2=n)

AM> In my ANOVA table I get the within values:
AM> Sum of Squares = 11972.56
AM> DF = 16
AM> Mean Square = 748.285

SE(diff)=SQRT(748.285*2/5)= 17.30069 (as you expected)

Now it's OK

Marta