|Date: ||Thu, 8 Jul 2004 23:10:48 +0200|
|Reply-To: ||Qinghai Huang <firstname.lastname@example.org>|
|Sender: ||"SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>|
|From: ||Qinghai Huang <email@example.com>|
|Subject: ||Re: dummy variable coding in regression|
|Content-Type: ||text/plain; charset="us-ascii" ; format="flowed"|
Thank you for your help.
>If you have created a dummy for each category then you can easily do
>different regressions with a different dummy left out each time, giving
>a different reference category. However, these signficance tests are
>not all independent of each other, so you should only test the
>comparisons that you are really interested in, and not compare
>everything with everything just in case there is a difference
>somewhere; that needs the proper use of post-hoc comparison methods.
Now I realize that regression and ANOVA has the same issue in the
post-hoc comparison. So hypotheses are very important. I will pay
attention to this!