I have two groups of individuals, each individual has a score measured multiple times and I have constructed a mixed model as follows with both individual slopes and intercepts allowed to vary:
lme(score ~ Group * Time , random = ~Time|Subject, data=df)
The data looks roughly like this at the group level:
I would like to do 2 things:
Estimate the time point at which the blue and red groups becomes equivalent in terms of score i.e. the red and blue line crossover, and also estimate a confidence interval for this value.
Test at certain time points e.g. Day 200 whether the blue and red groups are significantly different from one another in terms of score.
Time is treated continuously – not as a factor, because time points at which score is measured vary between individuals.