SAS Missing Values

Values of variables which are missing or unobtainable can be set to the SAS missing value symbol . (period). Missing values are usually simply disregarded when the data set is analyzed by a SAS procedure. Check the detailed notes on the procedure in the SAS manuals to see exactly how missing values are handled. Missing values often enter a data set through the use of the missover option of the infile statement in the data step. 公卫考场