The WEIGHT statement names a numeric variable that provides a weight for each observation in the input data set. The WEIGHT statement is most commonly used to input cell count data. See the section Inputting Frequency Counts for more information. If you use a WEIGHT statement, PROC FREQ assumes that an observation represents n observations, where n is the value of variable. The value of the WEIGHT variable is not required to be an integer.

If the value of the WEIGHT variable is missing, PROC FREQ does not use that observation in the analysis. If the value of the WEIGHT variable is zero, PROC FREQ ignores the observation unless you specify the ZEROS option, which includes observations with zero weights. If you do not specify a WEIGHT statement, PROC FREQ assigns a weight of one to each observation. The sum of the WEIGHT variable values represents the total number of observations.

If any value of the WEIGHT variable is negative, PROC FREQ displays the frequencies computed from the weighted values but
does not compute percentages and statistics. If you create an output data set by using the OUT=
option in the TABLES statement, PROC FREQ assigns missing values to the `PERCENT`

variable. PROC FREQ also assigns missing values to the variables that the OUTEXPECT and OUTPCT options provide. If any value
of the WEIGHT variable is negative, you cannot create an output data set by using the OUTPUT
statement because statistics are not computed when there are negative weights.

You can specify the following option in the WEIGHT statement: