Interaction between categorical and continuous variables

From PsychWiki - A Collaborative Psychology Wiki

(Difference between revisions)
Jump to: navigation, search
Stenstro (Talk | contribs)
Line 66: Line 66:
*Given the tedious nature of using the [[#Three Steps using SPSS | three steps described above]] every time you need to test interactions between categorical and continuous variables, I was happy to find Windows-based software which analyzes statistical interactions between dichotomous, categorical, or continuous variables, AND plots the interaction graphs.
*Given the tedious nature of using the [[#Three Steps using SPSS | three steps described above]] every time you need to test interactions between categorical and continuous variables, I was happy to find Windows-based software which analyzes statistical interactions between dichotomous, categorical, or continuous variables, AND plots the interaction graphs.
*The software is called [http://www.danielsoper.com/Interaction/default.aspx Interaction!] from a graduate student in the Information Systems department at Arizona State University. I found it very easy to use. There is also a good [http://www.danielsoper.com/Interaction/help.aspx Help section] on the website.
*The software is called [http://www.danielsoper.com/Interaction/default.aspx Interaction!] from a graduate student in the Information Systems department at Arizona State University. I found it very easy to use. There is also a good [http://www.danielsoper.com/Interaction/help.aspx Help section] on the website.
-
 
+
*When using the software to test the interaction between a categorical and continuous variable, you should center the continuous variable first in SPSS before using the Interaction! software to analyze the data.
   
   

Revision as of 00:29, 3 September 2007

Testing interactions between categorical and continuous variables follows the same basic steps as testing interactions between two continuous variables so there is content overlap between this page and the page describing interactions between two continuous variables.


Two approaches are described below:
(1) three steps to conduct the interaction using commands within SPSS, and
(2) Interaction! software by Daniel S. Soper that performs statistical analysis and graphics for interactions between dichotomous, categorical, and continuous variables.

*For a description of what is an interaction and main effects, please see the accompanying page about What is an Interaction?.


Contents


Three Steps using SPSS

There are three steps involved to calculate the interaction between two continuous variables.

Center the continuous variable


Create the interaction term


Conduct Regression



Interaction! software





◄ Back to Research Tools mainpage

Personal tools
Namespaces
Variants
Actions
Navigation
Interaction
Toolbox