PhD interview question when you don't know the answer How should you handle a question in an interview for a PhD program when you don't know the answer ?

Should you try to just say something even if this is wrong or just tell the interviewer that you don't know the answer?
In most cases, the interviewer does not care about the "answer", but rather about how you answer. I would answer honestly with something like "I do not know, would you like me to try and work it out?"