There was a straw poll that asked whether women appreciated men who had done National Service, and of the 14 who answered, 36 per cent said no / "No".
1. Would it be wrong if "National Service" is in lower case?
2. Should I use no or "No"?
Thanks.
It depends whether you are talking about national service as a general term, meaning the conscription which still exists for young people in many countries or if you are referring to the scheme of one particular country which actually uses that as its name. In the UK, during the Second World War, for example, conscription was officially named War Service or Military Service. Those would require capitalisation, but if you simply referred to the national service that they had to do, then you don't need capitals.
With the second part, I would leave "36 per cent said no". A straw poll can be done verbally, by email, by text, via a paper questionnaire (although it's usually verbal) so it's possible that those people didn't physically "say" anything. Their answer to the question was no so I would leave it as it is.