I am performing a prospective cohort study in an existing cohort study. The sample of participants I can use from this existing cohort is 190. I am using a Cox model to analyze the data and to get a Hazard ratio. But now I want to know what the power of the study is. How can I calculate it? I can't find it on the internet...
So I am doing a prospective survival analysis (in an existing cohort) of 190 participants, the exposure is divided either into three categories and continuous and the outcome is yes/no.
After that, I also want to calculate the power of the study when it is stratified for some covariates.
I am using SAS, so maybe there is an option in SAS for this?
I hope some of you can help me. Thanks in advance!