| Model
|
Use the
Model drop-down box to choose from the four different regression models available in Survival Analysis.
|
| Variables (survival times, indep., censoring, [optional] grouping)
|
Displays the standard variable selection dialog box for specifying the variable(s) with the survival times, a list of independent variables (covariates), the censoring indicator variable, and an optional grouping variable (for a stratified, by-group analysis).
|
| Specifying survival times
|
Specify survival times in three ways: Select one variable with survival times (For example, number of weeks surviving), select two variables containing the start and end dates respectively, or select six variables containing dates. These variables should contain the month (1 to 12), day (1 to 31), and year when the particular observation began (for example, when the patient was admitted to the hospital), and the month, day, and year when the observation was terminated (due to death/failure or censoring, for example, when a patient was dismissed from the hospital).
While processing the data, Survival Analysis computes the number of days that elapsed between dates and perform the analysis on this measure.
Note: If the value of the year is less than 100, Statistica automatically assumes that the year refers to the 20 th century; for example, the year 88 can be converted to 1988. The censoring indicator variable should contain the integer codes or text labels that uniquely identify complete and censored observations.
The (optional) variable with group codes should contain the integer codes or text labels that uniquely identify to which group (sample) each observation belongs. If no grouping variable is specified, a regular analysis can be performed on all data or a stratified analysis can be performed. In a stratified analysis, separate regression models are first fit to each group and the log-likelihoods for those models are summed up. This log-likelihood is then compared to that of the overall model (collapsed across groups).
|
| Code for complete responses
|
Enter the codes or text labels that were used in the censoring indicator variable to uniquely identify complete (uncensored) observations in this field.
Note: To review all codes in the respective variable, double-click on this field (or press the F2 key on your keyboard) to display the
Variable dialog box.
|
| Code for censored responses
|
Enter the codes or text labels that were used in the censoring indicator variable to uniquely identify incomplete (censored) observations in this field.
Note: To review all codes in the respective variable, double-click on this field (or press the F2 key on your keyboard) to display the
Variable dialog box.
|
| Codes (for groups)
|
Displays the
Select Codes for Grouping Variable dialog box, which is used to specify the codes or text labels that were used in the grouping variable to uniquely identify to which one of the two groups each observation belongs.
Note: To review all codes in the respective variable, double-click on this field.
The default selection is all codes.
|
