I have a mixed model (using lme in R) with a random intercept.
model <- lme(HCA ~ time, random=~1|subject, data=mydata)
my supervisor asked me to extract the slopes of HCA for each individual, so that I can use this in another model. I am in doubt here: as I have no random slope, wouldn't the slope be the same for each subject? Or should I add the intercept and the slope of time?
Here is the spaghetti plot