I was thinking of page rank, if any website has good page rank, then the click rate would also be higher?
higher the traffic = higher the page rank hence higher the earnings from adsense or any other network.
Not always, PR is only one of many parts of the Huge Code that they use to rank Sites. Of course it would make sense that getting Higher PR would get more Adsense earnings but who are we to know Google's big Plan!
I also don't think that PR has some influence on your income. Most important is your content. Also, I believe that more popular websites can count on bigger income just because they are popular (more advertisers choose them to put an ad on those website). But it is not directly realted with PR I guess.
Quality traffic is what you require to earn better adsense revenue,PR does not carry the Kudos it did a few years back it may have had some effect sometime back but these days its mainly have a niche site with quality traffic that gets the higher revenue.