Hi everyone. Mi name is Juan. I have a repeated measurement data with tree treatments: A (n=4), B (n=4) and C (n=4). The response variable (body temperature) was measured 30 times in each subject. Unfortunately, I have some missing values. I am using PROC MIXED to evaluate the effect of treatment of the response variable: proc mixed data=tmp3; CLASS Treatment ID Time; MODEL Temperature= Treatment Time Treatment*time/Residual; REPEATED / SUB=ID (Treatment) TYPE=AR(1); RANDOM ID (Treatment); LSMEANS Treatment Treatment*time/ PDIFF ADJUST=TUKEY; run; After I ran the program, I have the next statement in the LOG window: WARNING: The R matrix depends on observation order within subjects. Omitting observations from the analysis because of missing values can affect this matrix. Consider using a classification effect in the REPEATED statement to determine ordering in the R matrix. SAS is unable to calculate the effect of treatment or the least square means for each treatment. ¿How can I solve this problem? Thanks for your help
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