Up to now, you have
only used SPSS to create your own small SPSS file.
- The first SPSS run
created your ten cases.
- The second run used
the "data management" capability of SPSS to add two
new variables.
- The third run asked
you to use the "compute" procedure in SPSS to compute
VOTEGAIN--the number of electoral votes each state
gained between the 1990 and 2000 censuses.
- In these runs, you
used only a small number of cases and a few
variables.
- Through the rest of
the course, you will be using full data sets created
by others and stored as SPSS "system
files."
SPSS system files
combine raw data and data definition cards, so that
the data do not need to be entered anew each time, and
the variables can be referred to directly by the
8-character names assigned to them.
- SPSS system files are
designated as the "filetype" *.sav. [where
* = the name of the file]
- All SPSS system files
(and thus all *.sav files) are "binary" files, which
means that they are stored in computer code that
cannot be read by people from this planet.
- However, these SPSS
system files can be processed very efficiently by
SPSS.
SPSS can also generate
portable files that are encoded into ASCII form
and translatable, in turn, into system
files.
- These files can sent
via e-mail (if they are small enough).
- I have created a
"portable" file called "states2000.por" that I will be
sending you via e-mail.
- After you open
states2000,por, save it as
states2000.sav.
- Then you have your
own SPSS system file.
SPSS can also open Excel
spreadsheet files, which have the extension
.xls.
- I prepared an Excel
file containing data on voting turnout in the 2000
presidential election.
- voting2000.xls
was sent as an e-mail attachment.
- You were asked to
open that file and to save it as
voting2000.sav.
For Friday, I'm asking
you to add the voting turnout data to the states data,
using the SPSS Merge Files command. Here's what
you do:
- Launch SPSS and
access states2000.sav
- Pull down DATA
from the Menu bar.
- Move down to Merge
Files and choose Add Variables.