Why does my bathroom stink now that we just replaced the toilet?

1. Is there water in the bowl above the top of the drain opening?
2. When it was replaced, was all of the old wax seal scraped off of the toilet flange and the flange cleaned to ensure a good seal?
3. Was a new wax seal used between the toilet and the flange?
4. Was it sat on/twisted slightly during installation to ensure a good wax ring seal?
5. Does the toilet rock at all?
6. Have you made sure that the tub/shower and sink traps still have enough water in them to seal them?
7. Did you or the installer plug the hole in the flange while working to prevent sewer gases from entering the room/house?
8. Were any other changes made to the plumbing or venting recently?
9. Are you having any other plumbing issues?