(Adapted from Fischoff and Bar-Hillel (1984).) Two cab companies, the Blue and the Green, operate in a given city. Eighty-five percent of the cabs in the city are Blue;

the remaining 15% are Green. A cab was involved in a hit-and-run accident at night.

A witness identified the cab as a Green cab. The court tested the witness’ ability to distinguish between Blue and Green cabs under night-time visibility conditions. It found that the witness was able to identify each color correctly about 80% of the time, but confused it with the other color about 20% of the time.

What are the chances that the errant cab was indeed Green, as the witness claimed?