Suppose that in a particular region of Northern Pennsylvania methane was known to occur naturally (before fracking) on 7% of well sites, and that 14% of water wells on such sites showed methane contamination. Some years after fracking in the region began, 3.5% of all water wells throughout the region showed methane contamination. Suppose a recent home owner in the region puts in a new well and soon discovers methane con- tamination in the water. What is the probability that the methane is naturally occurring, and not a consequence of the fracking activity? Samples Natural Methane No Natural Methane Total Methane Contamination Found No Methane Contamination Found Total 10,000