Quote from ARogueTrader:
"Before their operations, they were randomly split into two groups, and half were prayed for by Christians, Jews, Buddhists and Muslims."
Poor study, poor design.
Buddhists don't believe in God.
Christians pray primarily to Christ.
Jews pray primarily to the God of Abraham.
Muslims pray to Allah.
Design a study where you isolated groups to determine effectiveness would have greater validity.
Also, how could you measure the sincerity of those praying, as nearly every religion makes note that the strength of prayer is in proportion to sincerity, and faith in God. Since there is no way to measure sincerity, or degrees of faith from shaky to perfect, the study is meaningless, as you would never know if prayer were being done effectively, and to what degree of efficacy.
While I do have belief in God, it has always seemed odd to me that someone would need to pray to God for something to be taken care of in this world.
God is all knowing. He knows all the problems. He knows all the solutions. God acts in whatever manner is best for all concerned in the long run.
Praying to God that you may know Him and learn to accept His will is quite different than asking God to solve a worldly problem.
Those who need to pray to God to solve the problems are demonstrating a lack of faith that He will do so if it is for the best. Just trust that He will do what is best.
God gave us mind to solve our problems, and a heart to know His love.