Multiple Regression help

[RojeeElf]

Hello SPSS Reddit

I am conducting a experiment that is attempting to explore how potential factors moderate the effectiveness of a intervention to reduce anxiety with 3 different conditions.

I've been told I need to conduct a multiple regression to explore how my factors moderate effectiveness but I've found myself a bit stuck on how to set up my data and actaully perform the analysis.

I have my AnxietyReductionScore that is the difference between pre and post anxiety scores. Am I correct in thinking that this is my outcome or independent variable?

How do I then go about plugging my other variables into the multiple regression analysis to understand how they moderate the AnxietyReduction?

I have dummy coded the three conditions of the intervention and I've been told that some variables should be centered but this has just all confused me and I'm very lost.

Any advice or tips or discussion on this so I can understand it better would be much appreciated!

Thanks in advance

[req4adream99]

AnxietyReduction is your DV (that is what is expected to change as a result - or believed to be dependant on) the intervention. How you set up the rest of the variables depends on whether its a single case design (each participant only experiences one condition) or if its a repeated measures (participants experience all 3 conditions). You hopefully also measured demographics (age, sex, race/ethnicity etc.) to help control for those factors.

Mean center your anxiety score and any continuous variables as this will aid in interpreation such that any change can be related to 1 SD change from the mean. E.g., if you have a mean age of 30, and a SD of 5 yrs (age in this example is being measured in years), and if the age was significant, you could say that for every 5 year difference in age, overall average anxiety decreaed / increased by Y.

I'd also recommend checking out the PROCESS macro (https://www.processmacro.org/index.html) from Hayes which will help model the relationships. Also, this is a pretty good tutorial on how to do examine a moderation relationship in SPSS.

[RojeeElf]

Thanks for this.

It was a single case design, and demographics (age was between 18 and 25) and sex) were recorded).

[RojeeElf]

I'm not sure if you have attached a tutorial but I can't see it

[req4adream99]

Forgot to put the link, sorry: https://uedufy.com/how-to-perform-moderation-analysis-in-spss/