I am finishing up my bachelor's thesis, and I am stuck with two issues. These are about Linear mixed Models.
My data set is about 5 time series which contain a discontinuity. Subjects were asked to forecast along the time series on what they would expect the next value be and ,at some point (period 33), a structural break was introduced (for example a change in the mean of the data). I would like to see how results vary,eg., DV=ERROR, across the different time series and before and after the "change" is introduced, having Subject ID as the grouping variable. These are my doubts
1. How can I graph my results? I would like to plot the interaction effect of two independent variables (type of timeseries and before/after the structural break).
2. How can I include the overall fit of the model? Is there something similar to R^2 I could use for mixed models?
Thank you in advance