User Guide

187
File Handling a
nd Fi le Transformations
File is already sorted on break variable(s). If the data have already been sorted by
values of the break variables, this option enables the procedure to run more quickly
and use less
memory. Use this option with caution.
 Data must b
y sorted by values of the break variables in the same order as the
break variables specified for the Aggregate Data procedure.
 Ifyouareaddingvariablestotheworkingdatafile,onlyselectthisoptionifthe
data are sorted by ascending values of the break variables.
Sort file before aggregating. In very rare instances with large data files, you may find it
necessary to sort the data file by values of the break variables prior to aggregating.
This optio
n is not recommended unless you encounter memory/performance problems
Aggregate Data: Aggregate Function
This dialog box specifies the function to use to calculate aggregated data values for
selected v
ariables on the Aggregate Variables list in the Aggregate Data dialog box.
Aggregate functions include:
 Summary functions, including mean, median, standard deviation, and sum.
 Number of cases, including unweighted, weighted, non-missing, and missing.
 Percentage or fraction of values above or below a specified value.
 Percentage or fraction of values inside or outside of a specified range.