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help > RE: Testing an interaction: split or not & issues with "0" coding
Jul 6, 2020 11:07 PM | Alfonso Nieto-Castanon - Boston University
RE: Testing an interaction: split or not & issues with "0" coding
Dear Lucas,
Almost but not quite; you may test that using a model of the form:
cases*males: coded as 1 for male cases, 0 otherwise
cases*females : coded as 1 for female cases, 0 otherwise
controls*males: coded as 1 for male controls, 0 otherwise
controls*females: coded as 1 for female controls, 0 otherwise
with a contrast [-1 1 1 -1] for a sex by cases interaction, and a contrast [.5 -.5 .5 -.5] for the main effect of sex
Hope this helps
Alfonso
Originally posted by Lucas Moro:
Almost but not quite; you may test that using a model of the form:
cases*males: coded as 1 for male cases, 0 otherwise
cases*females : coded as 1 for female cases, 0 otherwise
controls*males: coded as 1 for male controls, 0 otherwise
controls*females: coded as 1 for female controls, 0 otherwise
with a contrast [-1 1 1 -1] for a sex by cases interaction, and a contrast [.5 -.5 .5 -.5] for the main effect of sex
Hope this helps
Alfonso
Originally posted by Lucas Moro:
Dear Alfonso,
I'm very grateful for your comment.
May I still ask for clarity how to test for a "group by sex" interaction (only between-subject contrasts)?
When having the following strings:
- "cases": coded as 1 and controls as 0
-"controls": coded as 1 and cases as 0
-"males": coded as 1 and females as 0
-"females": coded as 1 and males as 0
will the contrast [1 -1 -1 1] test for such interaction, and [0.5 -05 0.5 -0.5] for the main effect of sex?
Thank you.
Lucas
I'm very grateful for your comment.
May I still ask for clarity how to test for a "group by sex" interaction (only between-subject contrasts)?
When having the following strings:
- "cases": coded as 1 and controls as 0
-"controls": coded as 1 and cases as 0
-"males": coded as 1 and females as 0
-"females": coded as 1 and males as 0
will the contrast [1 -1 -1 1] test for such interaction, and [0.5 -05 0.5 -0.5] for the main effect of sex?
Thank you.
Lucas
Threaded View
| Title | Author | Date |
|---|---|---|
| Lucas Moro | Jun 15, 2020 | |
| Alfonso Nieto-Castanon | Jun 18, 2020 | |
| Lucas Moro | Jul 2, 2020 | |
| Alfonso Nieto-Castanon | Jul 6, 2020 | |