Hey GerineL, thank you for your replies. I did a quick check to see if there were any significant differences at pretest, and there were! I was not expecting that, but it's good to see you say that it's a common thing. Anyway, after a bit of tweaking I've got a pretty ok dataset for parametric analyses, although it's rather small at 32 participants.
Just out of interest, does anyone know if a repeated measures MANCOVA is a thing? Because this is my basic design, and honestly I'm so confused about what to do with it!
The pretest and posttest sample sizes are the same, and the between subjects sample sizes are very similar. At this point I can't be sure if the follow up will end up with the same sizes, or even remotely close, as I am still collecting data - but it doesn't really matter if the follow up doesn't get included, it was just a nice addition.
Analysing pre- to posttest Believability and Discomfort change (which are posited as closely interrelated variables, hence the MANOVA part), and the comparison between three groups to see which peformed better/worse, are the key requirements for my study. As I say, the followup isn't too important. I would also like to explore what role CFQ has, as it is posited as a measure of the capacity to be able to change Believability and Discomfort, thus thought it might be included as a covariate. I've found no good reason yet to include the measures of STAI, BDI-II, and Word Syllables, and so they can effectively be disregarded.
I honestly love stats, and would love to be great at them, but they do confuse the hell out of me