Multiple Regression & Interactions

Posted by Stats Q on Aug 07, 2006; 1:01pm
URL: http://spssx-discussion.165.s1.nabble.com/Multiple-Regression-Interactions-tp1070140.html

Dear all,

Does anyone know whether there are sample size requirements for dichotomous
predictors in multiple regression? That is, for the dichotomous predictor,
what is the smallest number of cases per group that is allowed?

Also, I have another query regarding interpreting interaction effects in
SPSS’s multiple regression.  When a cross product term is created by
multiplying together a predictor which is positively associated with the DV
(e.g., happiness) and a predictor that is negatively associated with the DV
(e.g., depression), would the resulting product term be expected to show a
positive or negative beta coefficient? I’m sure there’s a really simple
answer to this.

Thank you in advance.
K S Scot