i have another problem
im trying to use PROC GLM
this is the coding im submittings
PROC GLM DATA=houses;
CLASS NOB;
MODEL PR=NOB;
MEANS PR/LSD HOVTEST=BARTLETT;
OUTPUT OUT=predicted P=Predicted R=Residuals;
RUN; 
But i keep coming up with this error message
113  PROC GLM DATA=houses;
114  CLASS NOB;
115  MODEL PR=NOB;
116  MEANS PR/LSD HOVTEST=BARTLETT;
ERROR: Only class variables allowed in this effect.
NOTE: The previous statement has been deleted.
117  OUTPUT OUT=predicted P=Predicted R=Residuals;
118  RUN;
can anyone help meee? 
thanks