Question

The researchers presented sub-jects with two urns { one containing 3 blue balls and 7 red balls, theother containing 7 blue balls and 3 red ones. subjects were given this information and then told that someone had drawn randomly 12 timesfrom one of the urns [with replacement]. subjects were told that thisdraw yielded 8 reds and 4 blues. they were then asked, \what is the probability that the draw was made from the rst urn

Answer 1

As I understand the question is asking the probability that the subjects drew from the first urn. Since they were only presented with 2 different urns the probability is 1:2 or a 50% chance that it waa the first urn.