Dear all, I have a general question about using PROC MIXED for split-plot design at random multiple locations. Suppose A-main plot, B-sub-plot, Rep-replications, Loc-locations. If Loc is fixed, I know the code should be proc mixed;
class Loc Rep A B;
model y =Loc|A|B;
random Rep(Loc) A*Rep(Loc);
run; However, if Loc is a random effect, then how should I revise the code? Should I also include Loc*A Loc*B Loc*A*B in random statement? What I think is proc mixed;
class Loc Rep A B;
model y = A B A*B;
random Loc Rep(Loc) A*Rep(Loc); Please correct me, thanks!! Further more, I know mathematically Loc + Rep(Loc) is equivalent to Loc + Rep + Loc*Rep in SAS, but which one is the correct way to understand the logic of experimental design? Suppose Loc is crossed with Rep, then A*Rep(Loc) should be changed to A*Rep + A*Loc + A*Rep* Loc ? Are they equivalent? Thanks for any input!!
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