My data set has the following variables:
- Treatment (4 types- fixed)
- Location (8 locations- fixed)
- Position in Location (3 positions per location- fixed)
- Samples are taken in each position (3 samples per position-random)
- Time (two sampling times - fixed)
- Mineralisation rate (as result of analysis of samples taken)
Two locations are used to test each treatment (ie 4 treatments, 2 locations per treatment, 8 locations total).
I want to do a split-plot (/nested?) repeated measures (/mixed model?) ANOVA in
R using the above variables.
Q.1. Does this sound suitable?
My goal is to see if there is an affect of 1) position, 2) treatment, 3) time and 4) interaction of all (ie pos*treat*, pos*time, treat*time, pos*treat*time) on mineralization rates.
Q 2. Is location nested in treatment? Is sample nested in position?
Q 3. What are the between- and within- factors?
Q 4. What is the subject/plot? - Is it the location or position or sample or rate?
Q 5. How can I put time as repeated measures in my R formula?
Q 6. Would you use aov, lme, or ezANOVA?
Q 7. How do I code the seperate independent variables, and their interactions into a proper R formula?
I have literally been trying to figure this out for days and I cannot seem to find an answer that makes sense...