Hi Steve, I have a question about error source in split-split plot design. I have combined two years of data as follows; class Year Rep Irrig Tillage Variety; model HJul24 = Irrig|Tillage|Variety; Random Rep(Year) Rep(Year Irrig) Rep(Year Irrig Tillage); Irrig was the main plot, Tillage was the subplot, and Variety was the sub-subplot in three replicates. I would like to consider year in the random model. My question is; should I include the Tillage in the random model or not. As I will say in the paper; Irrigation, tillage, variety, and their interaction were considered as fixed effects. Year, replicate, and their interaction with irrigation and tillage were considered as random effects. Thank you very much. Ahmed Attia
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