Astudy was designed to investigate the effects of two variables, (1) a student's level of mathematical anxiety and (2) teaching method, on a student's achievement in a mathematics course. students who had a low level of mathematical anxiety were taught using the traditional expository method. these students obtained a mean score of 420 with a standard deviation of 20 on a standardized test. assuming no information concerning the shape of the distribution is known, what percentage of the students scored between 380 and 460?