This is my first repeated measures analysis.
Subjects in two groups exercise until "peak" level. Blood is taken at baseline (prior to exercise), peak, 2hrs post, 24 hrs post, and 72hrs post. Levels of various proteins are measured in the blood samples.
Groups: 2 (mutation for disease, control)
Time Points (exercise): 5 (baseline, peak, 2hr, 24hr, 72hr)
Outcome: continuous variable (protein expression)
Is this description right?
If there is a group effect, then there would be an interaction between group and time. The lack of independence comes from the repeated measurements on the same subjects, so there should be a random effect with time. Because the two groups likely have different baseline measurements, I need to include both random intercepts and random slopes.
Does this seem like the right formula?
outcome ~ subject + group*time + (1 + subject|time)
Based on the comment below, is this right?
outcome ~ group*time + (1 + time | subject)