each advertiser placed on your site is calculated by your CTR and your signups.. basically if you offer quality traffic to the people advertising google will send higher paying advertisers on your site.
But you may want to edit your question and remove you CTR as it is against google TOS to share with others.. you could get your account deleted.
You can also make adsense scan only the words/phrases you want them to use, to get a higher paying ads, to make adsense only show ads related to XXXXXXXXXXX keyword phrases and non of the others on your site..
to block adsense from scanning crap keywords on your pages that are low paying put this code around the phrases that are low paying:
some keyword phrases that don't pay highly
and tell adsense to use these ones that are higher paying keyword phrases found on your pages:
keyword phrase that pays higherAnswer 2
You'll occasionally get very high clicks -- nothing to get too excited (or worried) about.
The CTR is the only thing you should worry about, as it's the only thing you can somewhat control (ad placement, colors, etc). eCPM is simply a factor of the CPC and CTR. $5.13 is pretty solid, but won't hold up with a pitiful CTR like that.Answer 3
Payment is based on keywords, advertisers bid on the keywords so the payment is constantly changing. Your site shows ads based on matching keywords on your site, so your site just happened to get a click for a high paying keyword.Answer 4
adsense :good keyword, get more money
adword :good keyword, pay more money