Is it rude to ask your professor to NOT put you as co-author of a paper?
To elaborate on the comment by Roland.

If you wrote the paper and analyzed the results, you have a strong claim of ownership on the paper (along with the graduate student who got the initial results). Depending on the depth of your analysis you may well be the lead author so it’s your call by right. 

If your professor is pushing for the result to be published then your name has to be on it. If you refuse it can’t happen. If they choose to publish without you it’s ethical misconduct and grounds for retracting the paper from wherever it’s submitted to.

The only diplomatic avenue here is that you push to correct the issues and then submit. Otherwise, politely say that you think the paper is not ready and that it is not publishable in its current state.