Yes. Basically, but the difference will be marginal. It is probabally a better use of your time to go out and get more links pointing to your site.
I have my own theory, but it's just that, a theory. I'm still looking for the proof either way as well.
Remember though, on-page is only a fraction of what counts. It'll only help you in cases where everything else is the exact same as your competitor. Get 10 unique and good backlinks for each minute you read that experiment and you'll be better off than doing a make over and implementing all of it. Remember google-bombing, miserable failure and bbq grill. All top spots with either no content or not related to the keyword anchor text at all.
One can use the <b> as well as the <strong> tag to make the text bold. I was wondering which is better from SEO point of view.
Yes it will definitely help earlier when I started blogging i used to post the content on normal font when I met a blogging expert he told me to do this then I started highlighting the main keywords I saw the changes very soon .