I have a list of patient samples that were tested at 3 clinical sites; for site 1, reagent lots 1 and 2 were applied; for site 2, reagent lots 1 and 3 were applied; for site 3, reagent lots 2 and 3 were applied. So this is a partially crossed design. Which mixed model I should use or actually both can be used:
Model 1: Y= Mean+ SITE + LOT + LOT*SITE + Error, OR Model 2: Y= Mean+ SITE + LOT (SITE) + Error,
I will appreciate any feedback!!