Does deleting the answer (which is wrong but unfortunately got upvotes) right?
Also, does reputation get reduced if I delete my own answer?
If you can fix the answer, fix it, don't delete it.
If it's really wrong (doesn't address the question at all, contains a bad bug, ...) and you can't fix it, you can delete it - it won't help future visitors.
I'd say don't delete it if it does contain good information but you found that it doesn't address the question completely - it might help someone else with a similar problem. (But edit it to note that it doesn't fix XYZ in the question, or introduces dependency ABC that is not appropriate here, or whatever reason made the answer "partially correct".)
You'll lose all reputation gained (or lost) from votes on that answer after deletion (
Lastly: don't go about mass-deleting anything. Only delete content that is really bad, might mislead people, etc. You're limited to five (I think) deletions of your own posts per day, and if you do that, an automatic flag is raised so that people can make sure you're not "rage-quitting", and undelete useful contents.
*no longer necessary, rep updates automatically