What does the below stat for a beta website indicate?
- Accepted answers percentage? Or
- Percentage of questions with answers?
It's exactly the same as any live site from my observation, so the percentage of answered questions compared to total questions that haven't been closed. The definition of an answered question is as per other sites:
So if a beta community has a problem with "drive by" questions where the OP never accepts an answer the community can still upvote good answers and it will no longer be treated as unanswered.