07-01-2015 11:06 AM
I am having an issue how to account for the extra error term in our mixed statistical model using the SAS mixed procedure. I want to treat it as a split-plot design to come up with an ANOVA table, and one error term should not include the factor L (see equation below).
My guess is something like:
Proc Mixed data=StrainGauges method=type3; class rep F R C L;
model S=F R C FR FC RC FRC L FL RL CL FRL FCL RCL FRCL/ddfm=kr;
However, I am not sure how to write the random statement (e.g. "Random rep(A*B*C)" or "Random rep(A|B|C)"). Can someone help me to write this code?
Thanks in advanced!
07-02-2015 03:30 PM
This is a case where you have several random effects, so the rep(A*B*C) is obviously not what you need (and it is just as obvious that it is the residual error).
A much better approach would be:
random intercept F R C F*R F*C R*C F*R*C/subject=rep;
Also in your model statement, be sure to represent interactions with the '*' operator. As it is now, this would treat FR, FC, RC and FRC as continuous (and undefined) variables.