Today, my psychology professor asserted that people can accurately predict random events roughly 60% of the time (he qualified this statement by saying that the actual figure lay around 57% and he was rounding). I asked him for an explanation of this claim, and in the following class discussion, he proceeded to assert that a random person predicting coin tosses would be right, on average, 60% of the time. I countered that that was impossible and the figure should be 50%, but he insisted on 60%. He said I was confusing the actual event with the prediction and that, while ratio of heads to tails should average 50/50, any person or machine making predictions should expect to average around 60% accuracy.
I discussed this claim further with a friend in the class, who said he had seen the study the professor referenced and insisted that a person predicting coin tosses would, in fact, average 60% accuracy. I insisted this was not possible, but he said that it was statistically proven, even though it seemed counterintuitive.
Later, I got a chance to engage the professor further, and he reaffirmed his assertion. He also added that a person predicting what card would be chosen at random from a deck of Zenner Cards would observe the same 60% success rate. He again countered my arguments by saying I was confusing the probability of the event itself with the probability of the prediction. I realize these figures are different (the ratio of heads to tails in a sequence of coin tosses may be 50/50 while the percentage of current predictions may differ substantially), but as far as I can see, the rate of accuracy for predictions should be 50% for a coin toss or 20% for the Zenner Cards no matter how you slice it.
I'm getting the feeling my friend and professor are misquoting whatever study they're trying to reference, but both were adamant about a 60% rate of prediction accuracy on coin tosses and Zenner Cards. Can anyone shed some light on what they might have been getting at?
