Adsense Payout Question?

[alankusa]

When targeting a keyword does Google payout based on search term or based on the page that the person searching lands on.

For example if I optimize a site / page for "My Keyword" and it pays well based on research.

Will I have the opportunity for a high paying AdSense click only if the person searching types in the phrase exactly finds it in the search results, clicks through to my site / page and then proceeds to click on an AdSense add.

Or will I have the same opportunity if they search for a different phrase that is only related to my subject they but still end up on the same page mentioned before, and then click on the AdSense add.

Which actually leads me to another question, which in a way is the same question just asked a little differently.

Are the payouts different depending how a person arrives at a particular page with AdSense on it. If a page is optimized for a specific keyword but they arrive there either by directly entering the URL, link from another page like an article site, website, or even a different search engine.

How is the payout greatly reduced or how is the payout amount decided on?