my english so sorry .
how many the ratio of straightdoper are scientist?about 30%?
Yeah, 30% sounds good.
Personally speaking, I am 100% scientist, but I imagine the OP wasn’t asking that.
I’d be stunned if even 10% of the active posters on this board are working scientists (or even those who work in fields with strong science bases, like medicine or engineering). But, I don’t think there’s any way to really tell. You could try a poll, but it’d be highly unlikely to be a scientific sample. (unintentional pun there.)
I’d say less than 10%. Computer programmers, on the other hand – we are a sexy majority.
There’s an ambiguity here. What I think you mean is what percentage of people here are either formally educated in science (or, rarely, have an equivalent alternate informal education) and actually do formal scientific research in either the academic world or industry.
You can also define “scientist” to be someone who has a scientific outlook on life. It used to be the case (maybe 100 years ago and earlier) that the common person could pursue scientific research at home. The progression of discoveries has lead us to the point where a lot of potentially promising avenues of research are very expensive to get into (e.g. expensive materials or equipment). Regulatory frameworks are now in place so that even if you discover a cure for cancer at home by testing grandma’s old cookie recipes mixed with cactus you gathered out in Arizona, you practically can’t sell it without the formal scientific establishment convincing the Government that it is effective and safe.
Not any computer programmer I’ve ever met! 
Speak for yourself!
(Actually, it’s an in-joke with someone not remotely related to this board.)
Are we not counting amateur scientists? OP, please be more specific.
Agreed. Define scientist. I am a programmer, not an academic. But doing science (using scientific methodologies and scientific habits of mind, doing experiments that compare a vs b to find out if I’m right about why something doesn’t work) are all in a day’s work for me.
ETA fixed italics (damned droid), elucidated a bit on what I mean by doing science.
I’m an engineer, but I’m retired, so I don’t know that counts. 
I am a working scientist at a research University.
I worked in the clinical trials department of a major pharmaceutical firm for several years before we were downsized. Does that count as being a “scientist” and chief bottle washer?
Honest to god scientist with letters after my name, a fully stocked lab that I run and everything.
PhD student in genetics here. It doesn’t get more sciencey than that, complete with long hours of tedium and little to no pay to show for it.
PhD in genetics and Biochem. Been in academic/industry research most of the time. Small research program now at small college.
Okay, and what percentage of straightdopers are mad scientists?
I’m only an MD but with moderately extensive training in college and med school to do research. I do mostly clinical and administrative work now, but regularly review studies, crunch numbers, and try to squeeze useful information out of the raw data that is my system’s patient population. I do put together analyses of this info for general review, and have presented some of my stuff at academic medical meetings.
Sometimes I’m mad, too. 
why, ***all ***of them of course.
That’s two questions, and would need to be answered with a Venn diagram.