Here is an answer in the negative by the Oxford philosopher of religion Richard Swinburne. It's a response to a scientific study of prayer on behalf of hospital patients, which showed no correlation between prayer and recovery. This passage is especially well-put:
"Suppose that I am a rich man who sometimes gives sums of money to worthy causes, and that I am very well informed and I know just how useful (or not) different gifts would be. I receive many letters asking me to give such gifts. Some foundation wants to know if there is any point in people writing such letters to me - do they make any difference to whether I give money to this cause or that? So the foundation commissions a study. Many people are enrolled to write letters to me on behalf of several causes rather than others in order to see whether subsequently I give more to those causes rather than to the other causes. In fact, let us suppose, I am normally moved by such letters; I think that the fact that many people take the trouble to write to me on behalf of some cause about which they care a lot is a reason for giving to that cause. But I now discover why I am suddenly bombarded with a stream of letters on behalf of certain causes; and I realise that on this occasion, unlike on other occasions, the letter writers have no deep concern for the causes for which they write. So of course on this occasion I pay no attention to the letters."