SPSS AnswerNet: Result
Solution ID: 100001386
Product: SPSS Base
Version:
O/S: WINDOWS
Question Type: Graphics
Question Subtype: Creation
Title:
Blank bar for unselected category
Description:
Q.
I have a categorical variable which I would like to display in a
bar chart. However, one of my categories was not selected by any
of my respondents. I can generate a frequency distribution and
bar chart for this variable, but the unselected category is not
included. How can I both generate a frequency distribution to
show a zero count for this category, as well as generate a bar
chart which also reflects a zero frequency?
A.
This is not a hard project. First, you'll need to create a constant
with a value of 1 to weight the cases in the data set by. After you
create that constant, save the data file. Then, create another data set
with a DATA LIST command. This new file will have only one case.
This case will contain the variable you wish to chart (with the value
that you wish to include in the chart) and the weight variable. The
weight variable should have a very small value, like .00001.
Then, merge this data set with the original, WEIGHT BY weight
variable, and then generate the chart either through the
FREQUENCIES command, or with GRAPH. You'll get a frequency of 0
for that value, and the resultant bar chart will have a "blank"
space for the bar.
The following sample job is illustrative:
* Create a sample data set.
INPUT PROGRAM.
LOOP #I = 1 TO 100.
COMPUTE x = (TRUNC(UNIFORM(3)) + 1).
END CASE.
END LOOP.
END FILE.
END INPUT PROGRAM.
EXECUTE.
* Compute the weight variable.
COMPUTE weight = 1.
SAVE OUTFILE = 'TMP.SAV'.
* Create a new file to merge with the original data.
NEW FILE.
DATA LIST /x 1 weight 3-8.
BEGIN DATA
4 .00001
END DATA.
EXE.
* Merge the data.
ADD FILES /FILE=*
/FILE='TMP.SAV'.
EXECUTE.
* Weight the data.
WEIGHT
BY weight .
* Generate the chart, here done with the FREQUENCIES command.
FREQUENCIES VARIABLES=x /BARCHART FREQ.