Here's an experiment I did from August/2009 to the first week of 2010(yes, concluded days ago). My observations got me excited so I decided to share something done in months with all of you.
I installed Analytics on pages which had AdSense in them. I made pages that would sleep(N) where N is a number of seconds, between AdSense loading and Analytics(at the bottom). autoflush on so content was sent to the client as soon as it was produced.
Slow pages ranked terribly, fast pages shot straight up. This is a good reputation site so I was able to get pages spidered quickly for my experiments, though the keywords used were not very important, so as to be able to test without spamming their index or anyone seeing the tests on relevant SERPs.
The observation which brought me here: Difference between fast and slow pages was about 30 positions.
I took analytics out in September and both pages ranked closely. In October I decided to test the contrary, once more, to be sure. Added analytics and the slow pages fell 30 positions. Remove analytics once more and pages shot up. Each boost/drop took about 10 to 11 days.
So that's the closest I've gotten to know that Analytics is sending back your page load speed in comparison to AdSense or some other Google widget on that same page, such as Maps.
Not only is it sending speed back but Google is also taking data collected on Maps, AdSense and Analytics in consideration for ranking purposes. Of course I can't be 100% sure, so this is only an observation which may be right or entirely wrong.