You will be given information about the percentage of accidents at night that were caused by Blue cabs, and the testimony of a witness who saw the accident.
The percentage of night-time cab accidents involving Blue cabs is based on the previous 2 years in the city. In different cities, this percentage was either 15%, 30%, 70%, or 85%. The rest of night-time cab accidents involved Green cabs.
Witnesses were tested for their ability to identify colors at night. They were tested in each city at night, with different numbers of colors matching their proportions in the cities.
The MEDIUM witness correctly identified 60% of the cabs of each color, calling Green cabs "Blue" 40% of the time and calling Blue cabs "Green" 40% of the time.
The HIGH witness correctly identified 80% of each color, calling Blue cabs "Green" or Green cabs "Blue" on 20% of the tests.
Both witnesses were found to give the same ratio of correct to false identifications on each color when tested in each of the cities.
In summary, you will be given information about the rate at which Blue cabs are involved in accidents at night, and you will be given the testimony of a witness. The witness was either "high" in accuracy (80% correct) or "medium" in accuracy (60% correct). In some cases, there was no witness. Your task is to estimate the probability that the cab in the particular accident was actually a Blue cab in each case. If you are sure it was NOT Blue, type 0, if you think it was certainly Blue, type 100, if you think that the probability was only 20% a Blue cab (that it was 80% likely Green), type 20; if you think the probability it was Blue was 80%, type 80. If you think it was equally likely a Blue or Green cab, type 50. Please do not type the percentage sign.
Express your judgment of probability it was Blue as a percentage (i.e., any number from 0 to 100). Do NOT type the percent sign.