Date:         Thu, 15 Jun 2006 18:06:04 -0400
Reply-To:     Sebastien <sebgogo@HOTMAIL.COM>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         Sebastien <sebgogo@HOTMAIL.COM>
Subject:      Re: ANOVA with Optimal Scaling technique and unequality of
              variance
Comments: To: Anita van der Kooij <KOOIJ@FSW.LEIDENUNIV.NL>
Content-Type: text/plain; charset=ISO-8859-1

Thank you for your answer. I've got some further questions:
1) Do you have any reference I can use to justify that equal variances is
not required?
2) Are there any assumptions behind optimal scaling?
3) What are the risks of type 1 and 2 errors with the optimal scaling
technique when the data have not equal variances?
It has been suggested to me to use Aligned Rank Transformation to study
interaction effect in a two-way ANOVA design, but it appeared that this
method is not suitable when variances are not equal, which is the case of
my data. That's why I'm looking for another method and I want to make sure
that this method can be used with confidence.
Sébastien.