How To Link Adsense To Google Analytics?

this is Google's offical answer:
To start linking accounts, look in your AdSense account for the link inviting you to integrate your accounts. This link appears on both the Overview and Advanced Reports pages. (If you don't see the link, please keep in mind that we're rolling out this feature gradually, and that you'll see the link only when we've activated it in your account.)

click on analytic settings first

then you can put your code: example


then you will see a link that says: edit adsense linking settings

<script type="text/javascript">
window.google_analytics_uacct = "UA-1454484S4s-4";
</script>