When the OUTPM= option is specified in addition to the RESIDUAL option in the MODEL statement,  and  are added to the data set as variables Resid, StudentResid, and PearsonResid, respectively. When the OUTP= option is specified,  and  are added to the data set. Raw residuals are part of the OUTPM= and OUTP= data sets without the RESIDUAL option.
具体可以在sas帮助里搜索The MIXED Procedure 会看到相关具体解释