In his paper "Probability Preferences in Gambling," American Journal of Psychology, Vol. 66 (1953), pp. 349-364, W. Edwards tells of a farmer who came to the psychological laboratory of the University of Washington. The farmer brought a carved whalebone with which he claimed that he could locate hidden sources of water. The following experiment was conducted to test the farmer's claim. He was taken into a room in which there were 10 covered cans. He was told that 5 of the 10 cans contained water and 5 were empty. The farmer's task was to divide the cans into 2 equal groups, 1 group containing all the cans with water, the other containing those without water. What is the probability that the farmer correctly put at least 3 cans into the water group just by chance?