User Guide

186
Chapter 8
To Aggregate a Data F ile
E From the menus choose:
Data
Aggregate...
E
Select one or more break variables that define how cases are grouped to create
aggregated
data.
E Select one
or more aggregate variables.
E Select an a
ggregate function for each aggregate variable.
Saving Aggregated Resu lts
You can add aggregate variables to the working data file or create a new, aggregated
data file.
 Add aggreg
ated variables to working data file.
Newvariablesbasedonaggregate
functions are added to the working data file. The data file itself is not aggregated.
Each case with the same value(s) of the break variable(s) receives the same
values for
the new aggregate variables.
 Create ne
w data file containing aggregated variables only.
Saves aggregated data
to an external data file. The file includes the break variables that define the
aggregated cases and all aggregate variables defined by aggregate functions.
The workin
gdatafileisunaffected.
 Replace
working data f ile with aggregated variables only.
Replaces the working
data file with the aggregated data file. The file includes the break variables that
define the aggregated cases and all aggregate variables defined by aggregate
function
s. This does not affect the original data file. The aggregated data file is
not saved unless you explicitly save the data file (File menu, Save, or Save As).
Sorting Option s for Large Data Files
For very large data files, it may be more efficient to aggregate pre-sorted data.