Use z-scores in Repeated Measures ANCOVA?

[rkprice]

Hi everyone,
My dissertation has participants answer three questions at four different timepoints in a video. For each timepoint, I have averaged the three questions for an average response per timepoint (4 scores). I also have a dichotomous between subjects variable, and two continuous covariates. My question is, do I need to standardize (z-scores) all the continuous variables within the analysis? Or can I just use the raw scores for each variable?

Thanks for your help.

 

[terzi]

Hi rkprice,

Standardization depends on your particular data and objectives. There's no need to do it unless you have a specific reason within your data/research.I'd say the decision is based mostly on what you can interpret easier.