I've conducted a questionnaire and got lots of data. I'm experienced in qualitative analysis, but I've never done advanced statistical analysis before so I'm unsure how to start. My supervisor is experienced in statistical analysis so I asked for guidance. She said she would do the statistical analysis and give it to me, and that isn't a problem as long as I understand and can defend her results. I said I'd like to do it myself as I want to learn the skills, so she said she would do it and I could watch so I understood. I'm very suspicious - is my supervisor trying to get her name first on the paper about my questionnaire by doing the statistics? It wouldn't be the first time she's put her name first on a paper about my work. Or is she just being helpful? I hate to think ill of her, she's been great in so many other respects but it seems a weird offer. Should I insist on doing it myself? I'm concerned it might affect my future prospects if I have to admit that my PhD research includes statistics that I'm not able to produce myself.

I can't guess your supervisors intentions however, if you write the paper and the majority of work is yours, YOUR name should be first. If you need clarification on this then ask another professor (or supervisor) at the university, or some other PhD students.

On the otherhand, from what I have gathered it is fairly normal to include your supervisors name on papers whilst you are a PhD student, though they should have made a contribution.

On the other otherhand (I have lots of hands), your PhD is YOUR PhD, if you want to do the stats then do them yourself, book yourself on a stats course or something (I taught myself). Your PhD supervisor is an advisor, not a manager, so you don't even have to ask, just do them yourself. If you get them wrong she'll crticise you, but at least you'll learn something! If she takes offence, then I suspect you are with the wrong supervisor (as long as you have made it clear you are going to do them yourself).

I agree with BigDave - doing a PhD is a research-training for academic life, so it makes no sense for her to do your stats - you need to learn to do them yourself.
And not to put the wind up you, but i agree that its odd that she isnt keen for you to do them yourself. Is she a 'micro-manager' generally, or is she just being possessive abut this one aspect?

She is a micro-manager generally. There have been situations where I've got in trouble for sending an email to one of my participants without clearing it with her first. With the last paper, I did the research study and she helped with analysis, I wrote the paper and she wrote the introduction as time was short and also did a bit of editing, then she put her name first because I had only done the actual work and she had done the literature bit for the intro and recommended which other papers should be used to back up the research (she claimed her bit was more complicated so her name should go first; of course she only told me this AFTER she had submitted it in her name!) The annual review panel made a big fuss over this and recommended in writing that any future publications should be in the name of the student. So you can see why I'm nervous about her intentions...

i would be a bit dubious. why cant she show you how to carry out stats tests wihtout actually doing it there seems no logical reason why she would do them for you and then give you them without something to gain from it

At least it sounds like others in your dept are aware of her weaknesses, so to speak. Could you have a chat with someone more senior about it? The fact that she needed say-so over an email to a participant sounds very extreme to me, and if thats typical of her supervision style, I imagine its going to be difficult to ever grow as an independent researcher and make decisions (and mistakes) on your own.
As comparison, my supervisors tend to let me just get on with it, and would probably be a little freaked if i cleared something like an email to a participant with them first....

Probably.

tbh at this point in her career doesn't she want to be last name on a paper rather than first? to show that she is a research leader and guiding her students towards bigger and better things?