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Title pretty much summarizes it. I know I can use the binomial distribution to calculate the chance of equal to or fewer than a certain number correct on a yes/no task where there's a 0.5 probability of being right on any trial. But what if you have 27 Yes/No trials where Yes is the correct answer on only 9 of the trials? Responding Yes to every trial would yield 9/27 correct responses while responding No to every trial would result in 18/27 correct responses. So the expected correct when the subject's Y/N responding is 50/50 is more like 10.5 than 13.5 out of 27. I need to calculate the probability that a certain number total correct is below chance...ltuff1

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