How to consider SERP and PR of first 10 sites while selecting Right Keyword?

what factors should I consider about the Search result(SERP) and PR of first pages' website?Let me clarify my point. I am trying to work with a Keyword " Healthy Relationship". Google planner shows that it has Global monthly search volume of 2400 where SERP(Google search engine result page) is 200000. Among them that keyword was used in title of 27600 websites. And the PR of first10 sites of SERP is more than 60 in total. Now Should I select it? what other things should I consider…
How to consider SERP and PR of first 10 sites while selecting Right Keyword?

See original post by Md Jahirul Islam