Page loading speed?? I don't think so. Google does not measure the page loading speed to provide rankings or SERPs. But, Google definitely likes sites which does not have XHTML errors.
absolutely not - there are many others factors involved such as backlinks - keywords etc Hope it helps...
I heard of few people saying this and its false. Since transfer speed can be slowed by by both sides and all the nodes inbetween, there's no way this can be in the ranking of pr.