Hi All, This is my first post in SAS community. I am SAS beginner and very low statistical knowledge in complex models. So, thank you in advanced for any suggestions and expect a comprehensive advise with the detail SAS codes from the expert too. I have done four cropping trials in RCB design. Each trial include four crops with four replications. For simple ANOVA analysis of each trial, it is fine. Beyond that, I would like to do combined analysis of these four trials in the mixed model. In this case, I would like to treat these four trials as one factor like four Managements since each trial is managed with different agronomic practices, e.g. irrigated for Trial 1, non-irrigated for Trial 2, late sowing for Trial 3 and late sowing for Trial 4 (but different location where high altitude/lower temperature condition). Then, I would like to investigate the two objectives from these experiments; (1) to compare the treatment means of four crops in combining all trials, and (2) to investigate any interactions between the crop (Treatment) factor and the management factor. I have read some analysis models that recommend "the analysis of combined experiments" of such data, using PROC MIXED in SAS but still confuse. These SAS examples are for different locations and times. The difference here is management rather than the location. My questions are - (1) Can I do combined analysis of these four trials? (2) If yes, whether should I assign Crop/Management as "Fixed" or "Random" effect in the Mixed model? (3) For objective 1, I would like to separate Treatment means by LSD test, how could I syntax in PROC MIXED model of SAS. (4) If LSD is not feasible in Proc mixed, what kind of mean comparisons should I perform? [I have tried, LSD is not recognized in the mixed model] (5) Should Replication be nested in Management factor? [I see some syntax Replication is nested in Location factor] I have tried this SAS code but not entirely confident whether it meets to my objectives or not. proc mixed data= combined method=type3;
class Rep Mang Treat;
model Yield=Treat;
random Mang Rep(Mang) Mang*Treat;
run; Thanks all.
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