Check this box to compute one-degree-of-freedom tests that break down each overall fixed-effect F -test.The tests are computed using the last level of each class variable as a reference level. These tests are particularly useful for analysis of exon -level data analyzed using transcripts as a BY variable . The results are saved in a separate output table with default suffix _amc .Refer to the LCOMPONENTS option in the SAS PROC MIXED MODEL statement documentation for additional details.