Bayes Theorem 101

"Bayesian analysis is an important concept for any scientist and skeptic to understand. It is extremely practical and is already used (whether or not it is explicitly named) in professions that need to deal with probability in a practical way, such as in medicine.

"Bayes Theorem makes explicitly clear several skeptical principles, including the need to consider predictive value, the impact of false positives, the need to consider an alternative hypothesis, and the need to put statistical significance into its proper context.

"In many ways, a Bayesian approach to knowledge is a skeptical approach."

http://theness.com/neurologicablog/index.php/what-is-bayes-theorem/

BTW, it can't be used to support claims of miracles. (link)