It so happened that I went to a Church with my room mate for he had to pray. I promised not to say anything bad for an hours time. In that hour, I read some horrifying books about introducing religion to children. Some of them were written for parents and more disgustingly, some of them catered small children of age 5-10, but that's not the point here. (To understand my grief, one is referred to a chapter on religion and childhood in the 'God Delusion')
Another thing that occurred to me, my otherwise not so religious room mate had gone praying because he is applying for a residency in medical school as an oncologist (He's a Hopkins/Princeton graduate with tonnes of research and practical experience). The question was, what is the probability of succeeding when you pray, or P(success|prayer) for a general situation. As the title suggests, we define the following quntities:
Event A : is any event where you can succeed or lose. (eg, running 3 miles, getting into MIT for grad school, trying not to eat a burger for 1 month etc)
Event B : You pray for event A
For the estimate of P(success|prayer), we need the following:
P(prayer|success) i.e. the probability that you'd prayed and you actually succeeded as well. (correct me if I am wrong here) = X
P(Success) : How many times in general you succeed or in other words, how much of a loser are you? = Y
P(Prayer) : How many times do you pray before and event A occurs. = Z
then, P(Success|prayer) = X * Y / Z
I know that estimating X, Y and Z is as difficult as estimating P(Success|prayer), but we can look at interesting special cases and for the benefit of our religious friends, we will try to maximize P(Success|prayer)
First special case is a devote religious person and a devote atheist, both equally losers in life, so Y is same for both. Since the person is very religious, he prays at every event A, so X == Z, hence, his P(Success|prayer) is Y. For a devote atheist, X == Z == 0, so we can with all non-rigorousness, claim that P(success|prayer) == Y. An awesome conclusion! So a religious person and an atheist are equally likely to succeed when (and if) they pray.
Now consider the problem that you want to maximize P(Success|prayer). We assume that loser ness thus Y is a personal quality independent of the the praying statistics (which is a valid assumption in the scientific world we live in). Hence we want to maximize X and minimize Z.
A way to maximize X is to pray only when you know you are going to succeed. So you can pray before going for a small walk that you will succeed in doing so, but don't ever pray for getting into MIT which is kind of unlikely (statistically speaking). Also, try to pray only for selective events and don't go around praying for all the stupid things in life.
In summary, an atheist and a complete devote (both idealized cases) are equally likely to succeed when they pray for it. And if you want to increase your chances of success because of praying, keep on praying for stupid things at which you'll surely succeed, but don't do that in excess.
People who are more intelligent than me should correct me in the above arguments :-)
ps : I thank Mr. Varun Kanade for the maximization argument
pps : Thanks to constant pricking by Mr. Karthik Shekhar, I hereby acknowledge that the above analysis is not valid at all.
ppps : pps , the above thing was not meant for you
pppps : why do I always do that?m