The degrees of freedom computations are described incorrectly in the PROC SURVEYMEANS documentation. This misprint occurs in the "Statistical Computations" section under Details in the PROC SURVEYMEANS chapter of the SAS/STAT 9.1 User's Guide as well as the SAS OnlineDoc 9.1 and later.

Table 70.2 reports the df for Domain D=7 as 2, and the df for Domain D=9 as 1. The correct domain df are 6 and 4, respectively. The description following Table 70.2 is incorrect and should instead be written as:

For Domain D=7 there are 8 clusters, then subtract 2 strata, resulting in 6 degrees of freedom. The reason that cluster 2 is included even though W = . is because that observation is not in the current domain D=7. Therefore, it is still counted for the df calculation. Note that the total number of strata is reduced to 2 because for variable Y, no statistics are computed for strata 1.

For Domain D=9 there are 7 clusters. Notice that cluster 2 is omitted from the df calculation because that observation falls in the current domain and has a missing weight. The total of 7 clusters minus 3 strata gives you the resulting 4 df.