I'm studying Cox Regression model on Survival Analysis.
While testing validity of Proportional Hazard model, I will use log(-log) graph method in SPSS.
First of all, I mention which procedure I'm following using SPSS.
I select Analyse --> Survival --> Kaplan-Meier --> defined time, status, factor. And then I select Save option and tick "Survival". "Group" variable is assigned as factor. And I get the following output "Sur_1". How can I fulfil the blank cell in the variable "Sur_1" ? If I'm able to fulfil them, I will compute log(-log Sur_1) and I plot it. Please help me thank you.