A witness is 80% reliable. The cab is still probably the other color.

In a city with 85% green cabs and 15% blue cabs, a witness who identifies cab colors correctly 80% of the time says a hit-and-run cab was blue. Most people guess it probably was blue, but because blue cabs are so rare to begin with, Bayes' theorem puts the real odds at only about 41%. People routinely ignore how common something is to start with, and focus only on how reliable the new evidence sounds.

— Amos Tversky and Daniel Kahneman, On prediction and judgment — ORI Research Monograph, 1972