To run the LOGISTIC REGRESSION procedure, select Analyze!Regression!
Binary Logistic from the drop-down menus to reach the dialog box to specify the
logistic model. Select CHD from the variable list and enter it into the Dependent
Variable box, then select and enter the covariates into the Covariate(s) box. The
default method is Enter, which runs the model with the covariates the user entered
into the Covariate(s) box. Click on OK to run the model. The output generated will
appear in the SPSS Viewer window.
The corresponding syntax, with the default specifications regarding the modeling
process, is:
LOGISTIC REGRESSION VAR¼chd
/METHOD¼ENTER cat age ch1 ecg smk hpt ch cc
/CRITERIA PIN(.05) POUT(.10) ITERATE(20) CUT(.5).To obtain 95% confidence intervals for the odds ratios, before clicking on OK to run
the model, select the PASTE button in the dialog box. A new box appears which
contains the syntax shown above. Insert /PRINT¼CI(95) before the /CRITERIA line
as shown below:
LOGISTIC REGRESSION VAR¼chd
/METHOD¼ENTER cat age ch1 ecg smk hpt ch cc
/PRINT¼CI(95)
/CRITERIA PIN(.05) POUT(.10) ITERATE(20) CUT(.5).Then click on OK to run the model.
The LOGISTIC REGRESSION procedure models the P(CHD¼ 1) rather than
P(CHD¼0) by default. The internal coding can be checked by examining the table
“Dependent Variable Encoding.”
The output produced by LOGISTIC REGRESSION follows:
Logistic Regression
Case Processing Summary
Unweighted casesa N Percent
Selected cases Included in analysis 609 100.0
Missing cases 0 .0
Total 609 100.0
Unselected cases 0 .0
Total 609 100.0aIf weight is in effect, see classification table for the total number of cases.
Dependent Variable Encoding
Original value Internal value
.00 0
1.00 1636 Appendix: Computer Programs for Logistic Regression