Physician IQ Scores For a random sample of IQ scores of 18 physicians, the mean is 124.2 and the standard deviation is 9.6 (based on data from a study conducted at the University of Wisconsin at Madison). Use a 0.05 significance level to test the claim that because physicians are a more homogeneous population than the general population, their IQ scores have a standard deviation less than 15, which is the standard deviation for the general population.