Science proves God doesn't exist?

In Eurekalert we find the following description of yet another book in what David van Biema in Time Magazine called an "atheist literary wave":

In God: The Failed Hypothesis. How Science Shows That God Does Not Exist, physicist Victor Stenger argues that science has advanced sufficiently to make a definitive statement on the existence or nonexistence of the traditional Judeo-Christian-Islamic God. He invites readers to put their minds--and the scientific method--to work to test this claim.

After evaluating all the scientific evidence--the studies done by
reputable institutions on the power of prayer; the writings of philosophers who have puzzled over the problem of God and of good and evil; the efforts of biblical scholars to prove the accuracy of holy scriptures; and the work of biologists, geologists, and astronomers looking for clues to a creator on Earth and in the cosmos--Stenger concludes that beyond a reasonable doubt the universe and life appear exactly as we might expect if there were no God. He convincingly shows that not only is there no evidence for the existence of God, but scientific observations actually point to his nonexistence.

I haven't read this book yet, so I won't comment on it, except to say that even Richard Dawkins, of The God Delusionfame, says he "learned an emormous amount from this splendid book."

What I will comment on is the "studies done by reputable institutions on the power of prayer". I have read the findings of some of these studies, and looked with wonder at their methodology - things like doing brain scans while a person is praying and trying to see what changes, statistical surveys of prayer results, double blind trials of intercessory prayer for heart surgery patients, etc.

Of this last one, Bishop Tom Wright said on BBC News, "Prayer is not a penny in the slot machine. You can't just put in a coin and get out a chocolate bar. This is like setting an exam for God to see if God will pass it or not."

There is an implication here that God is obliged to cooperate in such experiments, because otherwise he is a completely uncontrolled variable, thus invalidating the results. Unless, as I believe is usually the case, one of the assumptions made before the experiment is that prayer is a purely human activity - some sort of psychic force that has nothing to do with God, or spirit. In this case then, the experiment says nothing about God at all, and can't be used as evidence of his non-existence.

If it is assumed that prayer is an activity of the human spirit in conjunction with the Spirit of God, I wonder how the participants were selected, given that even for many (most?) Christians prayer appears to be a pretty hit-and-miss, "if it be thy will", "please give us what we need and not what we want" sort of thing, rather than a Holy Spirit driven conversation developing out of an intimate and very personal relationship with the person of God? Was any study first carried out to first find out who could really pray, and then select the prayer team from those?

Then there is the implication that the Judeo-Christian God is the same one as the Islamic one, despite their enormously different demonstrated nature and behaviour. And I've come across a few "gods" who would only be too happy to participate in trials like the above if only to perpetuate their deceptive ways.