Please help me with the analysis of my study.
Here is my design:
Each participant was asked 3 types of questions about the dates of historical events (fashion, sports and general history); I also asked the participants' to report their level of expertise in each of these domains and their need for closure. In each type of question, half of the advice were given by an expert and half by a non expert. My DV was the magnitude of the opinion change.
I predicted an interaction between the self-reported expertise and the adviser's expertise.
So, the tricky part in this design is that I have a continuous IV - the self-reported expertise (for sports, for fashion, and for general history) which is also repeated within participant.
When I entered it as a repeated IV in Multilevel Linear Model the SPSS showed the following error message: "The levels of the repeated effect are not different for each observation within a repeated subject. Execution of this command stops."